Borrazzo & Weitzel (eds.) Taphonomic Approaches to the Archaeological Record. Intersecciones en Antropología, Special Issue 1

Share Embed


Descripción

VOLUMEN ESPECIAL 1 - 2014

ISSN 1850 373X

¿Qué tipo de ciencia contribuimos a construir? Estrategia editorial de Intersecciones en Antropología

05

¿What kind of science are we contributing to produce? Editorial strategy of Intersecciones en Antropología

09

Articles Multi-service taphonomy. Shells, garbage, and floating palimpsests - L. A. Borrero

13

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) - H. Hammond

21

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the South-Central Andes - M. P. Babot, J. Lund and A. V. Olmos

35

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) M. Grosso

55

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) C. Landa, V. Pineau, E. Montanari and J. Doval

71

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) C. Balirán

85

Trampling fragmentation potential of lithic artifacts: an experimental approach - C. Weitzel, K. Borrazzo, A. Ceraso and C. Balirán

97

Volumen especial 1 - 2014

Contents

Taphonomic Approaches to the Archaeological Record Guest editors Karen Borrazzo and Celeste Weitzel

|

Editorial Board

Intersecciones en Antropología – Special Issue 1 – Taphonomic Approaches to the Archaeological Record Editors in Chief María A. Gutiérrez, Facultad de Ciencias Sociales, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA) – Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano (INCUAPA) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Ramiro Barberena, CONICET, Laboratorio de Paleoecología Humana, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo. Guest Editors Karen Borrazzo, CONICET – Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU), Buenos Aires, Argentina. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Argentina (UBA). Celeste Weitzel, CONICET – Área Arqueología y Antropología, Museo Ciencias Naturales, Municipalidad de Necochea, Buenos Aires, Argentina.

Associate Editors María Clara Álvarez, Facultad de Ciencias Sociales, INCUAPA, CONICET, UNCPBA. Karen Borrazzo, IMHICIHU, CONICET, UBA. Adolfo F. Gil, Museo de Historia Natural de San Rafael, CONICET. Mariela González, Facultad de Ciencias Sociales, INCUAPA, CONICET, UNCPBA. Agustina Massigoge, Facultad de Ciencias Sociales, INCUAPA, CONICET, UNCPBA. A. Francisco Zangrando, Centro Austral de Investigaciones Científicas (CADIC), CONICET, UBA.

Editorial Advisory Comitee László Bartosiewic, School of History, Classics and Archaeology, The University of Edinburgh. Edimburgo, Scotland. Eötvös Loránd University, Hungary. Robert L. Bettinger, Department of Anthropology, University of California. Davis, California, USA. Guillaume Boccara, Centre National de la Recherche Scientifique, L’École des Hautes Études en Sciences Sociales (CNRSEHESS). Paris, France. Luis. A. Borrero, Instituto Multidisciplinario de Historia y Ciencias Humanas - CONICET. Buenos Aires, Argentina. Claudia Briones, Universidad Nacional de Río Negro (UNRN) - CONICET. Bariloche, Río Negro, Argentina. Felipe Criado-Boado, Laboratorio de Patrimonio (LaPa), CSIC. Santiago de Compostela, Spain. Magarita Díaz-Andreu, ICREA - Universitat de Barcelona, Spain. Tom D. Dillehay, Anthropology Department, Vanderbilt University. Nashville, Tennessee, USA. Alejandro Grimson, Instituto de Altos Estudios Sociales, Universidad Nacional de San Martín – CONICET. San Martín, Buenos Aires, Argentina. Alejandro Isla, Programa Antropología Social y Política de FLACSO – CONICET. Ciudad Autónoma de Buenos Aires, Argentina. Robert L. Kelly, Department of Anthropology, University of Wyoming. Laramie, Wyoming, USA. Alberto Mendonça, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, UNRC - CONICET. Río Cuarto, Córdoba, Argentina. Walter Neves, Laboratorio de Estudos Evolutivos Humanos, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo. São Paulo, Brasil. Gustavo Politis, INCUAPA-CONICET, Facultad de Ciencias Sociales, UNCPBA y Facultad de Ciencias Naturales y Museo, UNLP. Olavarría, Buenos Aires, Argentina. Calógero M. Santoro, Instituto de Alta Investigación, Universidad de Tarapacá. Arica, Chile. Robin Torrence, The Australian Museum. Sydney, Australia. Robert H. Tykot, Department of Anthropology, University of South Florida. Tampa, Florida, USA.

1

2

| English Revision Raven Garvey, Department of Anthropology, University of Michigan, USA.

Reviewers of this special issue Huw Barton, School of Archaeology and Ancient History, University of Leicester, United Kingdom. Silvana Buscaglia, CONICET-Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU), Buenos Aires, Argentina. Universidad de la Patagonia Austral – Unidad Académica San Julián (UNPA-USAJ), Santa Cruz, Argentina. Diego Carabias, Director of ARKA - Arqueología Marítima, Valparaíso, Chile. Marcelo Cardillo, CONICET-Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU), Buenos Aires, Argentina. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Argentina. Gabriel Cocco, Área arqueología, Departamento de Estudios Etnográficos y Coloniales, Ministerio de Innovación y Cultura de la Provincia de Santa Fe, Argentina. Kelly Dixon, Department of Anthropology, University of Montana, USA. Catherine Dupont, CNRS Researcher, UMR 6566, CReAAH, Centre de Recherche en Archéologie Archéosciences Histoire, Rennes, France. Nora Flegenheimer, CONICET-Área Arqueología y Antropología, Museo Ciencias Naturales, Municipalidad de Necochea, Buenos Aires, Argentina. Irene Garibotti, CONICET- Instituto Argentino de Nivología, Glaciologia y Ciencias Ambientales, Mendoza, Argentina. María Gutierrez, INCUAPA-CONICET, Facultad de Ciencias Sociales, Universidad Nacional del Centro de la Provincia de Buenos Aires, Olavarría (Buenos Aires, Argentina) Thomas Jennings, University of West Georgia, USA. Carina Llano, CONICET-Laboratorio de Geoarqueología - Universidad Nacional de Cuyo, Mendoza, Argentina. Martijn Rene Manders, University of Leiden & Head of the Maritime Programme Cultural Heritage Agency of the Netherlands (RCE). Laura Miotti, CONICET- Departamento de Arqueología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina. Gaurav K. Mishra, CSIR-National Botanical Research Institute, Lichenology Lab, Lucknow, India. Justin Pargeter, Interdepartmental Program in Anthropological Sciences, Stony Brook University, New York, USA. Honorary Research Fellow, Center for Anthropological Research at the University of Johannesburg, South Africa. Maria Raviele, Institute of Museum and Library Services, Washington DC, USA. Mark Staniforth, School of Geography and Environmental Science, Monash University. Australia. Marcelo Weissel, Departamento Humanidades y Artes, Universidad Nacional de Lanús. Fundación de Historia Natural Félix de Azara, Buenos Aires, Argentina. A. Francisco Zangrando, CONICET-Centro Austral de Investigaciones Científicas (CADIC), Tierra del Fuego, Argentina. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Argentina. And anonymous reviewers. Article editor María Milena Sesar Design Mario Pesci Universidad Nacional del Centro de la Provincia de Buenos Aires Rector: Cr. Roberto Tassara Vicerrector: Ing. Agr. Omar Losardo Indizaciones Anthropological Literature (HOLLIS 009867824); Directorio y Catálogo LATINDEX (Folio No. 15044); Núcleo Básico de Revistas Científicas Argentinas (Resolución 1071/07, CAICYT-CONICET); Directory of Open Access Journals (DOAJ); Social Science Citation Index; Arts & Humanities Citation Index; SCOPUS; Zoological Record Portal SciELO Argentina

Intersecciones en Antropología es propiedad de la Facultad de Ciencias Sociales de la Universidad Nacional del Centro de la Provincia de Buenos Aires. Prohibida la reproducción de artículos sin su expreso permiso. Domicilio postal: Avda. del Valle 5737 - B7400JWI Olavarría, Argentina. ISSN 1850 373X (versión on line)

Inscripta en el Registro de Propiedad Intelectual Expte. 869051. La versión on line de Intersecciones en Antropología está disponible en el Portal SciELO Argentina (www.scielo.org.ar)

|

3

Contents ¿Qué tipo de ciencia contribuimos a construir? Estrategia editorial de Intersecciones en Antropología.....................05 ¿What kind of science are we contributing to produce? Editorial strategy of Intersecciones en Antropología............09

Articles: Multi-service taphonomy. Shells, garbage, and floating palimpsests - L. A. Borrero..................................................13 Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) - H. Hammond.....................................................................................................................21 Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the South-Central Andes - M. P. Babot, J. Lund and A. V. Olmos....................................................................................35 Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) - M. Grosso.............................................................................................................................................55 Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) - C. Landa, V. Pineau, E. Montanari and J. Doval.....................................................................................71 Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) - C. Balirán..............................................................................................................................................85 Trampling fragmentation potential of lithic artifacts: an experimental approach - C. Weitzel, K. Borrazzo, A. Ceraso and C. Balirán..........................................................................................................................................97

Intersecciones en Antropología - Special Issue 1: 03-03. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

4

|

|

5

¿Qué tipo de ciencia contribuimos a construir? Estrategia editorial de Intersecciones en Antropología Comité Editor desde esta perspectiva, a la que Borrero ha comenzado Esta breve introducción cumple dos funciones. a llamar Tafonomía sin límites, irrestricta o total. En primer lugar, presentar con gran orgullo y alegría Celebramos que las editoras hayan elegido nuestra el primer Volumen Especial de Intersecciones en revista para esta propuesta innovadora y provocadora. Antropología (IeA), titulado Taphonomic Approaches to the Archaeological Record, para cuya edición En segundo lugar, utilizamos este contexto de fueron invitadas Karen Borrazzo y Celeste Weitzel. presentación del primer volumen especial para Este volumen es una contribución pionera de una reflexionar sobre algunos aspectos del quehacer destacable diversidad en su contenido y robusta en editorial en el ámbito de nuestra disciplina. Esta términos de la inversión de trabajo que representa, reflexión nos conducirá a plantear algunos aspectos desde el desarrollo de las investigaciones originales de la historia de IeA, que nos permitirán, al mismo hasta el exhaustivo trabajo editorial que han realizado tiempo, contextualizar y comprender los desafíos a las editoras a cargo, que refleja la evolución de las los que nos enfrentamos en la actualidad. Justamente, aplicaciones tafonómicas en la Argentina desde los el proceso que lleva a la creación de este volumen primeras investigaciones realizadas en la década de especial es una parte central de esa realidad. Sobre 1980. Esta evolución es visible en diversos niveles, que esta base, describimos algunos aspectos de nuestra van desde los tipos de evidencia y contextos estudiados estrategia editorial. ¿Qué hay detrás de ella? Un desde esta perspectiva, las herramientas metodológicas determinado concepto de investigación al que empleadas y, por sobre todo, la madurez que se observa aspiramos a contribuir. O una suma de pequeñas en una integración cada vez más fuerte de la tafonomía decisiones en función de un objetivo de largo plazo. como vía de respuesta a interrogantes arqueológicos generales. La Argentina constituye un país pionero de América Latina en la propuesta y conducción de Breve historia y objetivos de estudios tafonómicos. El amplio y variado desarrollo Intersecciones en Antropología temprano de la zooarqueología en nuestro territorio ha permitido la rápida integración y expansión de En la Figura 1 presentamos el número de trabajos esta disciplina. El reconocimiento temprano de sus publicados desde el volumen 1 del año 2000 hasta contribuciones a las interpretaciones arqueológicas ha el volumen 15 del año 2014 (no se incluyen las permitido la consolidación de líneas de investigación reseñas de libro, que tienen un proceso de evaluación cuyos ejes temáticos giran casi exclusivamente en diferente, así como tampoco los obituarios). Un rápido tratar de resolver problemas arqueológicos desde análisis visual de esta información marca la evolución una perspectiva tafonómica, y esta maduración, a la vez, ha estimulado la incorporación de los aspectos teóricos y metodológicos de la tafonomía a otros registros arqueológicos. Este volumen entonces, de la mano de dos jóvenes investigadoras, refleja esa madurez que ha alcanzado la disciplina en nuestro país, con una propuesta cuya aplicación trasciende a los restos óseos exclusivamente. Los artículos de este volumen muestran la diversidad de evidencias (madera, conchas, líticos, almidones, etc.) Figura 1. Número de contribuciones publicadas en Intersecciones en Antropología   a los que es posible abordar (años 2000-2014). Intersecciones en Antropología - Special Issue 1: 05-07. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

6

Comité Editor - Intersecciones en Antropología - Special Issue 1 (2014) 05-07

explosiva que experimentó la revista, particularmente a partir del volumen publicado en el año 2006, en el que se duplicó el número de contribuciones. Este crecimiento continúa hasta la actualidad. Estos números muestran sólo la punta del iceberg en términos de la tarea editorial, ya que no se incluyen las contribuciones que no fueron aceptadas para publicación cada año. Por otra parte, el crecimiento que experimenta la comunidad científica vinculada a instituciones académicas o de investigación tales como el CONICET o las Universidades Nacionales se refleja claramente en estos números. La comunidad académica que envía contribuciones a esta revista ha cambiado y crecido en forma ostensible desde el inicio de este período hasta la actualidad. Los nuevos requisitos de estas instituciones para acceder, permanecer o promocionar a la carrera del investigador, categorización docente o para financiar proyectos de investigación, han puesto en marcha una serie de desafíos para los autores, evaluadores y editores. Esto requirió, y aún requiere, cambios en la estructura y estrategia editorial de la revista. Cada publicación científica tiene un perfil académico determinado, que se construye sobre la base de los objetivos de largo plazo establecidos por el Comité Editorial. Estos objetivos se materializan a través de innumerables decisiones pequeñas tomadas en forma permanente. La situación se puede resumir en dos grandes dimensiones, que, sumadas, construyen nuestra estrategia editorial: qué mensaje buscamos transmitir y cuáles son los receptores que aspiramos alcanzar.

Estrategia editorial de IeA Todo sistema de evaluación sano y eficiente se basa en criterios objetivos y precisos. Es lógico realizar críticas −muchas veces acertadas− a determinados criterios de evaluación de la calidad de un trabajo o de una revista científica. Dicho esto, creemos que estos criterios son necesarios en un sistema científico que aspire a superarse a sí mismo en el tiempo. Las revistas científicas nacionales no son ajenas a las exigencias y evaluaciones de calidad de carácter nacional e internacional. En nuestras instituciones (i.e., Universidad, CONICET, FONDECyT, entre otras), las áreas vinculadas a las Ciencias Sociales y Humanas se han hecho eco, si bien con particularidades y tiempos propios de la disciplina, de las exigencias pautadas para otras áreas del conocimiento. Es así como ha crecido la demanda de publicar en revistas indexadas. Las revistas son medidas a través del sistema de indexación, que funciona como una base de datos especializada. Las variables fundamentales a la hora

de clasificar una revista son la calidad científica y editorial, la visibilidad y la accesibilidad. Estamos de acuerdo en que, a los fines prácticos de un sistema de evaluación, deben existir formas de medir calidad y otorgar puntajes a nuestras publicaciones. Buscando canalizar esta necesidad, se trabajó desde un comienzo para que IeA fuera indexada en las bases de datos nacionales e internacionales más prestigiosas a escala mundial (Social Science Citation Index, Arts & Humanities Citation Index, SCOPUS, Anthropological Literature, Directorio y Catálogo LATINDEX, Núcleo Básico de Revistas Científicas Argentinas, Directory of Open Access Journals, Zoological Record, Redalyc, entre otras). Sin embargo, sabemos también que las indexaciones han adquirido un rol en dicho sistema que soslaya los objetivos comerciales que algunas de estas conllevan, al ser parte de las propias empresas editoriales. Es necesario mejorar el conocimiento sobre cómo se construyen los índices y cuál es su función real, para otorgarles el lugar adecuado como medida de calidad de las publicaciones en nuestra disciplina. En este sentido, creemos que urge un debate y diálogo entre autores, editores y evaluadores a fin de reflexionar sobre estos aspectos particulares de las Ciencias Sociales y Humanas, y diseñar caminos conjuntos que unan intereses diversos.

¿Qué se publica en IeA? El perfil académico que adopta una revista en el largo plazo no se desarrolla en aislamiento de las condiciones económicas y sociológicas de la comunidad donde se inserta. Hay dos tendencias que inciden en múltiples publicaciones científicas en forma global. En primer lugar, se puede verificar un notorio aumento en la magnitud de trabajos publicados en publicaciones consideradas de alta calidad en sus respectivos ámbitos. Un rápido análisis en Science Direct del número de trabajos publicados por el Journal of Archaeological Science (Elsevier) desde la década de 1980 hasta la actualidad muestra un ejemplo evidente (http://www.sciencedirect.com/ science/journal/03054403). Esto ha llevado en forma reciente al lanzamiento de un nuevo formato de publicación denominado Journal of Archaeological Science. Reports (http://www.journals.elsevier. com/journal-of-archaeological-science-reports/), el cual buscará absorber una parte de la producción usualmente enviada a la publicación tradicional. La irrupción en gran escala de las diversas ramas de la Public Library of Science (PLOS) es otro ejemplo. En segundo lugar, cabe afirmar que los recursos económicos disponibles en las instituciones públicas que financian muchas de estas revistas no han podido crecer en forma equivalente a la magnitud de la

¿Qué tipo de ciencia contribuimos a construir? Estrategia editorial de Intersecciones en Antropología producción científica que canalizan en la actualidad. Esto genera una asimetría creciente entre los requerimientos que marca una comunidad académica determinada y los recursos económicos y humanos disponibles para satisfacerla. Este es el caso de IeA. Y es también el caso de numerosas publicaciones de Arqueología en el mundo, que han pasado de ámbitos de sustentación exclusivamente universitarios a otros que implican diversas formas de asociación a empresas editoriales que cubren los costos y ofrecen canales más amplios de difusión. Un ejemplo reciente es el paso de Archaeology in Oceania, fundada por Alfred R. Radcliffe-Brown en 1930, de la University of Sydney a Wiley en 2013 (http://sydney.edu.au/arts/ publications/oceania/about.shtml). Anthropological Forum, creada en 1963 en el ámbito de la University of Western Australia, provee un caso particularmente interesante, ya que ha sido adquirida por Taylor & Francis pero permanece bajo la órbita académica de dicha universidad (http://www.tandfonline.com/toc/ canf20/current#.U8vsS4B5M0c). Actualmente, en IeA se reciben y evalúan más de 60 manuscritos por año. Esto ha generado la necesidad de ampliar el Comité Editorial, aunque esto provee tan sólo una solución parcial. Desde sus inicios, IeA cubrió todas las ramas de las Ciencias Antropológicas. Con el crecimiento de la comunidad científica en la Argentina, el surgimiento de nuevos campos disciplinares cada vez más específicos, y una afluencia creciente de contribuciones de Chile, Uruguay, España, México y EEUU, entre otros países, reconocemos que esta tarea resulta cada vez más hercúlea. En los siguientes años, la revista se enfrentará a la necesidad de redefinirse en ciertos aspectos. Esto resulta imprescindible para garantizar su viabilidad en un mediano y largo plazo. IeA pone especial énfasis en el proceso de evaluación, al que consideramos una de las etapas clave del proceso editorial. Nuestro banco de evaluadores es amplio, diverso y multinacional, y se actualiza constantemente. En la actualidad, IeA trabaja con un mínimo de tres revisiones y toda decisión sobre un manuscrito se basa en un balance de las opiniones recibidas. Dependiendo de la decisión de los revisores convocados, se llega a contar con cinco o más evaluaciones para un trabajo. De este modo se minimiza el peso de evaluaciones arbitrarias o poco sustentadas, aunque lógicamente no se elimina el carácter subjetivo del proceso de revisión por pares. Creemos que una exigencia elevada sólo puede beneficiar a la disciplina en su conjunto. Desde el punto de vista de la salud de un sistema académico en el largo plazo, nuestra postura es simple: sólo debemos preocuparnos al enfrentar sistemas poco exigentes de selección editorial (aún cuando, circunstancialmente, esto nos lleve a enfrentar el rechazo de manuscritos).

7

En este marco, creemos que, si son adecuadamente diseñados y evaluados, los volúmenes especiales en publicaciones periódicas proveen una poderosa herramienta de transmisión de información sobre campos temáticos específicos. Existen excelentes ejemplos en la arqueología mundial (Current Anthropology, Journal of Archaeological Science, International Journal of Osteoarchaeology, entre muchos otros). Este es el caso de Taphonomic Approaches to the Archaeological Record. Creemos que este volumen marcará un hito en la historia de la disciplina, así como un camino de ida en nuestra tarea editorial a través de la incorporación de estos volúmenes especiales como herramientas de difusión del conocimiento arqueológico.

¿A quiénes se dirige IeA? Podemos analizar esta pregunta a partir de otra. ¿Existen fronteras en la producción y difusión del conocimiento? Nuestra respuesta es un NO rotundo. Intersecciones en Antropología es una publicación sustentada desde un punto de vista institucional y económico por la Facultad de Ciencias Sociales de la Universidad Nacional del Centro de la Provincia de Buenos Aires de la República Argentina. En este sentido, es lógico que el principal receptor sea la comunidad científica de la Argentina, y así lo es actualmente. Sin embargo, desde un comienzo, IeA ha luchado por trascender esta escala local de difusión del pensamiento; alcanzó oportunamente la escala del sur de Sudamérica y aspira a trascenderla. La publicación de ciertas contribuciones en inglés es, en este sentido, una herramienta clave. Es el medio a través del cual podemos dar mayor alcance a nuestro pensamiento local, así como dar lugar a la publicación de trabajos procedentes de otros ámbitos académicos del mundo. Creemos que es una virtud exponer nuestras ideas a una multiplicidad de ámbitos académicos diferentes. En síntesis, hemos utilizado el espacio que brinda este primer volumen especial para comentar ciertos aspectos que hacen a la estrategia editorial de Intersecciones en Antropología. Creemos firmemente en un sistema académico perfectible mediante la aplicación de criterios explícitos y “universales” de exigencia. Y aspiramos a exponer la investigación del sur de Sudamérica en un contexto global. Esto implica trascender la imposición de fronteras artificiales en la difusión del conocimiento. La génesis del conocimiento es local. Su difusión y evaluación deben ser globales.

8

Comité Editor - Intersecciones en Antropología - Special Issue 1 (2014) 05-07

|

9

What kind of science are we contributing to produce? Editorial strategy of Intersecciones en Antropología Editorial board This brief introduction plays two roles. In the first place, we proudly present the first special volume of Intersecciones en Antropología (IeA): Taphonomic Approaches to the Archaeological Record, with Karen Borrazzo and Celeste Weitzel as guest editors. This volume is a pioneer contribution with a remarkable diversity of contents and solid in terms of the efforts invested, both in the original research and the thorough editorial work carried out by the editors. This first volume reflects the development of taphonomic approaches in Argentina since the early research in the 1980’s. This evolution is evident in the remarkable range of contexts and materials studied from this perspective, the diversity of methodological tools applied, and specially, in the maturity shown by the increasing incorporation of taphonomy to answer broad archaeological questions. Argentina is a pioneer country in the application of taphonomic studies in Latin America. The early and varied development of zooarchaeology in Argentina enabled a prompt incorporation and expansion of the discipline. The recognition of the substantial contributions of taphonomy to archaeological interpretation led to the consolidation of lines of research focused in solving archaeological problems from a taphonomic perspective. This development stimulated the incorporation of the methods and theory of taphonomy to varied archaeological records. This volume, edited by two young researchers, reflects the maturity of the discipline in Argentina, with a proposal that goes beyond the application of taphonomy exclusively to faunal remains. The papers in this volume show the various materials (wood, shells, lithic, starch, etc.) that can be approached from a taphonomic perspective as part of what Borrero defines as ‘unbounded Taphonomy’. We celebrate that the guest editors have chosen our journal for this innovative proposal. In the second place, we take this opportunity to make some considerations on several points of the editorial work in our

discipline. Throughout this reflection we will bring up some aspects of the history of IeA that allow us to contextualize and understand the editorial challenges that we face in the present. Precisely, the process that led to the creation of this special volume is a central aspect of this reality. On this basis, we present some tenets of our editorial strategy. What underlies an editorial strategy? We suggest that a particular conception of science to which we aspire to contribute to. Or the sum of innumerable small decisions aimed at a long-term goal.

BRIEF HISTORY AND GOALS OF INTERSECCIONES EN ANTROPOLOGÍA Figure 1 shows the number of papers that were published in the journal since volume 1 in 2000 until volume 15 in 2014 (book reviews –with a different reviewing process- and obituaries are not included). A glimpse of this information reveals the bursting evolution of the journal, particularly since 2006, when the number of published papers doubled in comparison to previous issues. This growth continues in the present. These numbers are just the ‘tip of the iceberg’ regarding the editorial work, as rejected papers are not included here. The growth experienced by the scientific community linked with academic or research institutions, like CONICET or the State Universities, is clearly reflected

Figure 1. Number of papers published by Intersecciones en Antropología (years 2000-2014).

Intersecciones en Antropología - special Issue 1: 09-11. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

 

10

Editorial board - Intersecciones en Antropología - Special Issue 1 (2014) 09-11

in these numbers. The academic community that submits papers to IeA has grown ostensibly from the beginning of this period to the present. The latest requirements of national research institutions for admission and promotion as a researcher, research fellow or to obtain funding have set several challenges for authors, reviewers and editors. This required, and still requires, changes in the journal’s structure and editorial strategy. Every scientific publication has a specific academic profile, built according to long-term goals set by the editorial board. These goals are achieved through countless small decisions. The situation could be summarized in two major dimensions: which message do we want to communicate and who are the receivers we are aiming for. The sum of these two factors builds an editorial strategy.

EDITORIAL STRATEGY OF IeA Every healthy and efficient editorial system is based on unbiased and precise criteria. It is valuable -and usually correct- to discuss and criticize particular criteria about the revision of the quality of a paper or of a scientific journal. Having said this, we believe that these criteria are a key part of a scientific system that seeks to improve itself over time. National scientific journals are not divorced from the national and international requirements of quality control. In our own institutions (Universities, CONICET, FONDECyT, among others), Social Sciences and Humanities areas have followed the global requirements ruled by other fields of knowledge, although considering the special features of each discipline. In this way, a growing demand for publishing in indexed journals has developed. Journals are ranked through an indexation system in the form of a specialized journals data-base. The essential variables for ranking a journal are scientific and editorial quality, visibility and access. We agree with quality control and ranking measures for our publications as a part of an evaluation system. Since the beginnings we worked to get IeA indexed in the most prestigious national and international data-bases (Social Science Citation Index; Arts & Humanities Citation Index; SCOPUS; Anthropological Literature; Directorio y Catálogo LATINDEX; Núcleo Básico de Revistas Científicas Argentinas; Directory of Open Access Journals; Zoological Record; Redalyc, among others). Nevertheless, we are also aware that indexations have taken a role that contributes to the commercial goals that some of them entail, since they are part of the publishing companies themselves. We need to improve our knowledge on how the indexes are built and which is their actual role in order to give

indexations their appropriate place as a measure of the scientific quality of our publications. We believe that a dialog and debate among authors, editors and reviewers are needed to design paths that combine the diverse interests and aspects of Social Sciences and Humanities with the global indexation requirements.

About IeA The academic profile of a journal in the longterm is not isolated from the economic and social conditions of its community. Two trends influence scientific publications in a global manner. In the first place, there is a notorious increment in the number of articles published in journals considered of high quality within each field. A quick analysis in Science Direct of the number of papers published in the Journal of Archaeological Science (Elsevier) since the 1980’s to the present depicts this trend (http://www.sciencedirect. com/science/journal/03054403). Recently, this led to the creation of a new publication format: Journal of Archaeological Science. Reports (http://www.journals. elsevier.com/journal-of-archaeological-science-reports/) that incorporates part of the manuscripts usually sent to the original journal.The massive irruption of the Public Library of Science (PLOS) is another example. Secondly, the economic resources of the public institutions funding many of these journals have not experienced a similar growth to that of the current scientific community and its published production. This creates an increasing asymmetry between the requirements of the scientific community and the available economic and human resources. This is the case of IeA. And it is also the case of many Archaeology journals in the world that had to recur to publishers with the capacity to cover the costs and offer broader worldwide diffusion. A recent example is the merge of Archaeology in Oceania, founded by Alfred R. Radcliffe-Brown in 1930 in the University of Sydney, with Wiley in 2013 (http://sydney.edu.au/ arts/publications/oceania/about.html). Anthropological Forum, created in 1963 in the University of Western Australia, represents a particular case since it was taken over by Taylor & Francis but it remains in hands of that University (http://www.tandfonline.com/toc/ canf20/current#.U8vsS4B5M0c). Currently IeA receives and reviews more than 60 papers over a year. As a first measure, the editorial board had to enlarge its team, but this is only a partial solution. Since its beginning the scope of IeA included all the disciplines within Anthropological Science. However, with the growth of the Argentine scientific community, the advent of numerous new and specific fields, as well as the increasing number of contributions received from Chile, Uruguay, España,

Editorial strategy of Intersecciones en Antropología México and the USA, among other countries, our editorial work is becoming an increasingly demanding task. In the following years the journal will have to face a redefinition of some aspects. This is imperative to guarantee its viability in the mid- and long-term. IeA pays special attention to the review process, a stage that we consider key in the editorial process. Our reviewer board is wide, diverse and multinational, and is updated on a permanent basis. Currently, IeA considers three revisions per manuscript as a minimum number and the final editorial decision on each paper is based on a balance of all reviewers’ comments. According to reviewers’ opinions, the final decision on a manuscript can be based on five or more reviews. This process minimizes the relative incidence of biased or poorly sustained reviews, although it does not remove the subjective character of the peer-review process. We believe that a rigorous review process benefits the discipline globally. From the point of view of the long-term health of any academic system, our position is quite simple: we only need to be concerned when dealing with undemanding editorial systems of scientific selection (even though when, eventually, this leads to the refusal of manuscripts). Within this framework, we believe that if special issues of periodic journals are appropriately reviewed they provide a powerful tool of information transmission on specific fields. There are very good examples of this in world archaeology (Current Anthropology, Journal of Archaeological Science, International Journal of Osteoarchaeology, among many others). This is also the case of Taphonomic Approaches to the Archaeological Record. We are confident that this special issue will become a milestone in the discipline, also representing a one-way path in our editorial work through the incorporation of special issues as a tool in broadcasting archaeological knowledge.

11

Who is IeA addressed to? We can analyze this topic by answering the following question: Are there boundaries in knowledge production and diffusion? Our reply is: absolutely not. IeA is funded by the Facultad de Ciencias Sociales de la Universidad Nacional del Centro de la Provincia de Buenos Aires de la República Argentina. Therefore, it is natural that the Argentine scientific community is its main receiver, and it actually is indeed. However, since the beginning, IeA has struggled to go beyond the local scale of knowledge diffusion, reaching the scale of southern South America opportunely, and currently attempting to transcend it. Publishing papers written in English language is a key factor in this endeavor. This is the means to widen the scope of our local production, as well as to incorporate works produced by researchers from other scientific communities worldwide. We consider a virtue to bring local ideas to multiple and different academic spheres. In sum, we have taken the opportunity provided by this first special issue to comment on several central aspects of the editorial strategy of Intersecciones en Antropología. We firmly believe in a perfectible academic system by means of explicit and ‘universal’ quality criteria. And we look forward to show southern South American research in a global scale. This implies to transcend imposed artificial boundaries for knowledge diffusion. The production of knowledge is local. Its diffusion and evaluation have to be global.

12

Editorial board - Intersecciones en Antropología - Special Issue 1 (2014) 09-11

|

13

Multi-service taphonomy. Shells, garbage, and floating palimpsests Luis Alberto Borrero Received 20 August 2013. Accepted 14 February 2014

ABSTRACT We discuss the importance of widening the scope of taphonomy, arguing that it is critical to study of different classes of materials within this framework. We introduce several examples related to the deposition of marine shells and garbage. In particular, we focus on debris generated by tsunamis Keywords: Taphonomy; Garbage; Tsunami; Palimpsest.

RESUMEN TAFONOMÍA MULTISERVICIO. VALVAS, BASURA Y PALIMPSESTOS FLOTANTES. Se presenta una discusión acerca de la importancia de ampliar el campo de la tafonomía, considerando distintas clases de materiales. Se presentan varios ejemplos, relacionados con la depositación de valvas marinas y el estudio de la basura en diferentes contextos. Se desarrolla en particular el caso de los desechos derivados de la acción de tsunamis. Palabras clave: Tafonomía; Basura; Tsunami; Palimpsesto.

INTRODUCTION The concept of “site formation processes” is necessary “to build a sound foundation for archaeological inference” (Schiffer 1987: 8). According to Schiffer, taphonomy is one of several research strategies −along with ethnoarchaeology or experimental archaeology− that inform our understanding of the principles of site formation (Schiffer 1987: 8-9). Schiffer also suggested that what we see today is a distorted image of what was deposited in the past and that these distortions can be rectified (Schiffer 1976). His view is flawed in at least two ways, however. First, such distortions rarely can be rectified. Instead, they can be understood and used to select the most appropriate scale of analysis. Second, taphonomy goes well beyond supplying principles of site formation, generating independent paleobiological, paleoclimatological and palaeoecological data (Gifford 1981). The goals of taphonomy are the subject of intense discussion (Lyman 2010; Thiébaut et al. 2010; Dominguez-Rodrigo et al. 2011). As I have said elsewhere, “taphonomy studies the constant tension between preservational and destructive

media” (Borrero 2011: 270). The focus is not on bones specifically, but on these tensions as recorded in different materials. This is coincident with the efforts of Peter Hiscock (1985) and others (Bordes 2003; Borrazzo 2006) who are developing systematic studies of taphonomic effects on lithic tools, for example. Moreover, Dominguez-Rodrigo et al. (2011) recently noted that taphonomy has broadened its referential scope to incorporate humans as taphonomic agents, and that “the non-organic materials of archaeological (and palaeontological) sites might also be studied taphonomically” (Dominguez-Rodrigo et al. 2011: 4). Broadening the scope of taphonomy is desirable since it will facilitate comparative research (Coumont et al. 2010). This objective is more or less convergent with the goals of classic formation studies (Schiffer 1987), adding an interest in preservation that goes beyond establishing links between behavior and discard. It is becoming clear that this extension of taphonomic studies is operative at several levels (Borrazzo 2011a; Eren et al. 2011; Ratto and Carniglia 2013).

Luis Alberto Borrero. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU). Saavedra 15, 5to. piso (1083ACA), Buenos Aires, Argentina. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 13-20. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

14

L. A. Borrero - Intersecciones en Antropología - Special Issue 1 (2014) 13-20

Taphonomy should integrate studies of different material types. For example, what we learn through the taphonomic study of bones can guide our expectations for other materials (Borrero 2011: 269270; VanDerwarker and Peres 2013), and this concept of “multi-service taphonomy” has applications even beyond the realm of archaeology. Indeed a number of taphonomic studies of non-bone organic materials already exist, including pollen (Campbell 1999), rock art (Brady and Gunn 2012), and even oil (Lipps 2008). But there is also a taphonomy of non-organic materials such as photographs −including the study of formation processes and posterior alterations (Fiore and Varela 2009: 21)− and of lithics, as I have mentioned. The subject of all these discussions is the same: the tensions between preservationa­l and destructive media, and the information that can be gleaned from those tensions. Naturally, all of these studies are focused on differential preservation, but only some of them are simultaneously interested in decoding the environmental signal associated with taphonomic marks. Of course, a comparison between corroded and well-preserved plumbing also provides information about the environment in which each is found. Studies restricted to the description of preservational differences are incomplete since it is an understanding of the processes that led to the differences that is really important (Behrensmeyer and Kidwell 1985). All these approaches to taphonomy can be improved and expanded by experimentation. Good examples of such research are the studies by Fernández Jalvo et al. (2010) on pollen found on coprolites, Borrazzo (2011b) on the morphological changes to artifacts deposited on the surface, Blanco and Lynch (2011) on the ways of producing rock art, and Pickering and Egeland (2006) on percussion marks on bones. This broad approach to taphonomy may be useful in a number of ways. Importantly, neither new disciplines nor new terminology is required to do the job. What is required is a theoretical and methodological program to make taphonomy fully operative. The importance of creating relevant frames of reference cannot be exaggerated (Dominguez-Rodrigo 2012). I will introduce some examples that not only work at different scales, but also serve more than one discipline (Hayashida 2005).

HIGH− AND LOW−ENERGY TAPHONOMY It is useful to refer to the Taphonomically Active Zone (TAZ), where destructive potential is high. This is a common concept in discussing preservation of shell beds (Ritter et al. 2013), but it is applicable to a variety of other situations as well (i.e., places with high incidence of carnivore activity, etc.). Identifying TAZs is a way to separate areas where preservation

is unlikely from those areas within a region where preservation is likely to be good. For example, it could be useful to classify archaeological shell-middens in terms of their topographic location or distance from the upper intertidal zone; in other words, to differentiate shell-middens within and distant from the locally defined TAZ. Experiments can then be designed to reproduce the conditions in the TAZ and derive expectations for preservation. TAZs are appropriate places to learn about the formation and preservation of the archaeological record. For example, I generated a model of contamination of archaeological sites by modern vertebrate bones. A number of factors can contribute to such contamination including, trampling, generally associated with the regular use of paths by guanaco (Lama guanicoe) and some degree of overlap between paths, the places were animals died, and the distributions of prehistoric settlements (Borrero 1990). Of course, I was able to recognize this process in a place where all −or most− of these factors coincide, a true TAZ. The high ratio of archaeological sites contaminated with recently incorporated guanaco bones indicated the importance of the observation. However, the conditions of my model are not always met and its applicability is limited to locations where those conditions exist. Still, even slight variations in those conditions help us develop new criteria that can be useful for identifying intrusive bones (Borrero 2001). So, in a sense, the utility of any such modeling exercise is the ability to go from obvious cases represented by TAZs to the more common archaeological situations away from such places. It is important to bear in mind that taphonomic processes occur in both high and low energy environments (Petraglia and Nash 1987). We know something about areas where disturbance is high, but we also need to know which places are only mildly affected or relatively unaffected by the main taphonomic processes. We must also be ready to extract the environmental information implied by those very markers of little disturbance, be it a paucity of weathering, corrosion, or any other process. Combining disciplines like taphonomy and ethnoarchaeology can provide a clearer picture of formation processes. For example, it is a useful exercise to examine the ethnoarchaeological record associated with the discard of mollusks by the Ambarra on the Australian coasts with TAZ criteria in mind (Meehan 1982). This should help us understand the likelihood of preservation of mollusks discarded by the Ambarra and, in turn, inform comparisons with other regions. At least two important depositional principles are derived from the Ambarra study: (1) in some cases associated with the exploitation of Batissa violacea and Crassostrea amara “usually only flesh, but

Multi-service taphonomy. Shells, garbage, and floating palimpsests sometimes a few shells as well, is carried back to home base” (Meehan 1982: 117). Similar observations are available from ancient sources (Cook 1946: 51). This indicates the existence of more than one depositional setting for mollusk shells, only one of which would be archaeologically visible. As asserted by Bailey (2007: 205),“If the individual episodes of shellgathering that make up a large mound, or the individual assemblages of stone tools that make up a layer in a stratified cave, had been dispersed across the landscape, many would now be lost to view”, and will be affected by destructive processes. In Bailey’s words, this constitutes a particular archaeological phenomenon: a spatial palimpsest. (2) It was observed that “shells were relocated several times during a single occupation, becoming intermixed with shells from previous occupations or dead shells that formed a normal part of beach debris, or else they were washed away by high tides” (Meehan 1982: 117). Beyond the implication that our expectations for finding ordered occupational sequences should be low, the information provided by this study is basically taphonomic. It clearly states that palimpsests of cultural and natural processes are to be expected. Also, it says something about the location of the deposits, the expectations for associated artifacts and the energy of the processes involved.

GARBOLOGY Garbage studies1, a classic actualistic approach to site formation, clearly demonstrate that formation processes and taphonomy are closely aligned For example, Weberman, the infamous garbologist, describes his rapid discovery of the benefits of scavenging garbage from Bob Dylan’s garbage can: “I lifted the lid … I reached in and the first thing … that I pulled out of Dylan’s garbage was a half-finished letter written by Bob Dylan to Johnny Cash” (Weberman 1980: 1). It goes without saying that the utility of this approach requires a taphonomic approach; Weberman’s great discovery −the Dylan letter− was preserved because it was not in contact with humid rejects –like diapers, which were also present− or other destructive materials. Since Weberman’s discovery, a less “owner”focused, more systematic approach to garbage was developed (Rathje and Murphy 1992). The distinction between items that preserve in the long-term and those that preserve in the short-term was crucial for the success of the approach. Needless to say, garbage is not restricted to bones. Undoubtedly, garbage studies are a basic element for the construction of discard theories. They offer evidence of factors like “messiness of the items discarded” (Murray 1980), otherwise difficult to obtain but nonetheless important for understanding the archaeological record. Returning to Weberman,

15

at some point he asked himself if he was trespassing the rights of other people (or specifically those of Bob Dylan), but concluded that in the post-Watergate times that action was acceptable. Unfortunately, when he applied the same tactics in 1980 to the garbage of expresident Richard Nixon, Secret Service agents arrested him (Rathje and Murphy 1992). Leaving legal problems aside it is important to learn about garbage. I intend to demonstrate this by examining a particular class of garbage: floating garbage.

FLOATING PALIMPSESTS Some of the most impressive sources of highly mobile debris are tsunamis. It was recently stated that “to accurately predict future coastal hazards, one must identify the records that are generated by the processes associated with these hazards and recognize what will be preserved” (Arcos et al. 2013: 9). In other words, taphonomy is required to understand important ecological issues like the oceanic distribution of the five million tons of waste generated by the March 11, 2011 tsunami in Japan. The NOAA agency modeled the potential distribution of that waste, indicating that “debris could pass near or wash ashore in the Northwestern Hawaiian Islands in spring 2012, approach the West Coast of the United States in 2013, and circle back to Hawaii in 2014 to 2016” (NOAA 2011: 1). Not all five million tons of waste was strictly floating. The debris is classifiable into items that have sunk and flotsam –floating garbage− which, 15 months after the tsunami, had already reached the coasts of North America, between California and Alaska. This material −after a long stay in the ocean environment− was mostly restricted to plastic, but even a HarleyDavidson in a container was found. Obviously, there are taphonomic processes acting on these materials. For example, perforating organisms accelerate the sinking of different materials, particularly wood. Generally speaking, many remains decayed swiftly, up to the point when they were reduced to floating glass and especially polyethylene and polypropylene that cover thousands of square kilometers (United Nations 2012: 41). This material will slowly disintegrate, to become what we generically call microplastic (Erikson 2012). In contrast, we must remember that ultraviolet rays will swiftly break up plastic in desert environments (Weisman 2007). From a taphonomic point of view the floating materials can be separated in “high” and “low-windage”, depending on “how much of it is exposed to the wind” (Erikson 2012: 20). The Ministry of Environment of British Columbia, Canada, like other institutions along the Pacific coast, issued bulletins with instructions on how to deal with debris from the tsunami, explaining which were dangerous.

16

L. A. Borrero - Intersecciones en Antropología - Special Issue 1 (2014) 13-20

No doubt on the basis of taphonomic and forensic considerations, it was reported that “It is extremely unlikely any human remains from the tsunami will reach Canada” (Ministry of Environment 2012: 1). So far I have presented a detailed example focused on the last high impact tsunami on the coasts of Japan, but this is only one of many examples. For example, in Chile there are records of tsunamis at least since the 1550s (Urrutia de Habun and Lanza Lezcano 1993). More impressive, there are records of 22 tsunamis for the Galápagos Islands between 1960 and 2011 (Arcos et al. 2013), at least 245 tsunamis for the Pacific between 1900 and 1983, and 229 for the Mediterranean in historic times (Auger 1993: 119). On the other hand, a depositional record testifying to the existence of tsunamis and related phenomena was found at the Peruvian coast (Spiske et al. 2013). This is not always the case, but clearly indicates the tsunamis can sometimes be easily recognized, while other times they are nearly impossible to detect. Perhaps some indications can be found at archaeological sites disturbed or destroyed by tsunamis (Clague and Bobrowsky 1994; Cole et al. 1996; Hutchinson and MacMillan 1997), a subject that has received general treatment (Renfrew 1979; Estevez 2005). For example, Colin Renfrew writes that when excavating an archaeological site affected by a tsunami, “large chunks of debris immediately recognizable as intrusive” should be found (Renfrew 1979: 578). Needless to say, the importance of taphonomy for this evaluation cannot be understated. It was generally accepted that tsunamis debris can be easily identified and isolated from other deposits like those resulting from storms. However, difficulty arises from what Arcos and collaborators call “amalgamated deposits” (palimpsests; Arcos et al. 2013). An endless variety of artifacts result from the action of tsunamis. However, when discussing the effects of specific events, like that of Japan, it is possible to identify items of Japanese origin (United Nations 2012), but usually their link with specific phenomena can only be achieved through contemporaneous testimonies, as demonstrated by the study of Galápagos (Arcos et al. 2013: 16). Unfortunately, there is almost no way of telling the age of floating microplastic (Humes 2013: 133 ss.). In cases like that of the 1975 Makran Trench tsunami in the northern Arabian sea it was a combination of “concentrations of angular shell fragments, articulated bivalves (out of life position)”, particle size and a predominance of foraminiferous marine taxa that was used to identify the relevant sediments (Pilarczyk and Reinhardt 2012: 129). A recent “Pepsi label from plastic bottle” and other debris helped to identify “the reworking of the upper sediments” (Pilarczyk and Reinhardt 2012: 130). In the case of the 1755 tsunami on the Gibraltar coast there

were evidences of palimpsests in the form of Pliocene foraminifera within a Late Quaternary deposit. Also, the remains of a hand grenade that “was in use during the 18th Century”, that was related to alternative hostile scenarios between 1727 and 1779-1783 were found (Rodríguez-Vidal et al. 2011: 187). Any improvement in the taphonomy of tsunamis should be useful in the program of understanding and maintenance of the oceans. Summing up my impression of the debris resulting from tsunamis, it must be stated that these floating palimpsests are going to be the basis of future taphonomic evaluations. A wide and comparative concept of taphonomy is necessary for these evaluations. I cannot see any utility in separating the study of different raw materials by discipline; information on the distribution of plastic is useful in the evaluation of the destiny of other classes of debris, for example. In this way we can learn about the velocity and direction of drift in the ocean, materials’ resistance to and persistence through different processes, and locations where flotsam is likely to appear in the future. There are short −and long− term ecological implications, and there are also different lifecycles for different materials, all of which are the stuff of taphonomy. I have focused on tsunamis, but they are not the only forces circulating materials in the ocean. The observation rate of different debris in the ocean was high for the last several decades. During the Atlantic crossings of the papyrus boat Ra in 1969-1970, flotsam was recorded every day (Heyerdahl 1972). In 2005, even the supposedly limpid environment of Kingman reef in the Pacific, to which access is restricted, was heavily affected by the plastic “rain” (Weisman 2007). The preservational-destructive tensions in those diverse assemblages of artifacts will determine which will survive and where. There are other classes of materials, like wastewaters, that are discharged into the oceans in massive amounts and that have even a greater ecological impact (George 2009); their relationships with the survival of different materials still needs to be elucidated. Inspection of the oceans constantly reminds us of the recently recognized importance of humans as coevolutionary agents (Odling-Smee et al. 2003; Rick and Erlandson 2008). However, within this panorama of garbage and extensive contamination, not everything is negative; floating garbage wreckage sites may have constructive uses as well. For example, there is archaeological evidence for opportunistic scavenging of wood from European wreckages to construct huts at Herschel Island, Chile (Solari 1992). Also, there are probably many Robinson Crusoe-style stories in which wreckages offer more than construction material. However, the main point is that the best contribution that can be made with those materials is to understand and, if possible, control them.

Multi-service taphonomy. Shells, garbage, and floating palimpsests CONCLUSIONS I have presented some examples trying to convey the notion that the range of applications of taphonomy should be unrestricted. I chose to focus on actualistic cases, somewhat related to ethnoarchaeology, garbology or ecology, as a way to demonstrate the wide array of taphonomic studies that currently exists. Results are not always spectacular, problems are not always solved and usually we learn that we really do not know as much as we believed. Generally speaking, most of our difficulties in accepting this, or even accepting that taphonomy is a crucial component of our research agenda, result from viewing the link between the archaeological record and our interpretations as a fingerprint, when in fact it is only a footprint. We should not expect precision and that is the reason why palimpsests are not our worst enemies, but the valuable preserved parts of the record (Borrero 2011). They are so important that instead of the usual plangent cries that go with the discovery of palimpsests, we should hear cheering shouts. I would like to emphasize that my defense of the palimpsest is not based exclusively on its offer of different levels of organization not appreciated at the ethnographic scale (Bailey 1981; Binford 1981, among others), but it is predicated on the notion that they are the usual form in which the record is presented to us for study. In accordance with Lyman, what I am suggesting here can be read as a misuse of the term taphonomy, that “exacerbate confusion and misunderstanding” (Lyman 2010: 1). However, I feel that real confusion arises when we try to maintain our trade within the narrow confines of tradition. In the end, the name of the discipline is not important. What is important is that if this claim for a unity of taphonomy is wrong, no major harm will be done to the disciplines of archaeology, ecology or paleontology, yet, there is always danger in ignoring the need to “proceed taphonomically”.

Acknowledgements I want to express my gratitude to Karen Borrazzo and Celeste Weitzel for their kind invitation to participate in their Symposium at the XVIII Congreso Nacional de Arqueología Argentina, La Rioja. I also want to thank Ivana Ozán for her help during the preparation of this chapter. Comments by the reviewers were very helpful in clarifying aspects of this chapter. Finally, I want to thank Raven Garvey who helped improving the translation to English.

17

REFERENCES Arcos, M. E. M., B. T. MacInnes, P. Arreaga, F. RiveraHernández, R. T. Weiss and P. Lynett 2013 An amalgamated meter-thick sedimentary package enabled by the 2011 Tohoku tsunami in El Garrapatero, Galapagos Islands. Quaternary Research 80: 9-19. Auger, D. 1993 The New Catastrophism. The Importance of the Rare Event in Geological History. Cambridge University Press, Cambridge. Bailey, G. N. 1981 Concepts, timescales and explanations in economic prehistory. En Economic Archaeology, edited by A. Sheridan and G. Bailey, pp. 97-117. BAR International Series 9. Archaeopress, Oxford. 2007 Time perspectives, palimpsests and the archaeology of time. Journal of Anthropological Archaeology 26: 198-223. Behrensmeyer, A. K. and S. M. Kidwell 1985 Taphonomy´s contribution to paleobiology. Paleobiology 11: 105-109. Binford, L. R. 1981 Bones. Ancient Men and Modern Myths. Academic Press, New York. Blanco, R. V. and V. Lynch 2011 Experimentos replicativos de grabados en piedra. Implicancias en el arte rupestre de la localidad arqueológica de Piedra Museo (Santa Cruz, Argentina). Boletín del Museo Chileno de Arte Precolombino 16 (1): 9-21. Bordes, J-G. 2003 Lithic taphonomy of the Châtelperronian/ Aurignacian interstratifications in Roc de Combe and Le Piage (Lot, France). In The Chronology of the Aurignacian and of the Transitional Technocomplexes: Dating, Stratigraphies, Cultural Implications, edited by J. Zilhao and F. d’Errico, pp. 223-244. Trabalhos de Arqueologia 33. Instituto Português de Arqueologia, Lisboa. Borrazzo, K. 2006 Tafonomía lítica en dunas: una propuesta para el análisis de los artefactos líticos. Intersecciones en Antropología 7: 247-261. 2011a Tafonomía lítica y pseudoartefactos: el caso de la península El Páramo (Tierra del Fuego, Argentina). Intersecciones en Antropología 12: 155-166. 2011b Tafonomía lítica en la estepa patagónica: experimentación y registro arqueológico de superficie. In Bosques, montañas y cazadores. Investigaciones arqueológicas en Patagonia Meridional, edited by L. A. Borrero and K. Borrazzo, pp. 127-153. CONICETIMHICIHU, Buenos Aires.

18

L. A. Borrero - Intersecciones en Antropología - Special Issue 1 (2014) 13-20

Borrero, L. A. 1990 Taphonomy of Guanaco Bones in Tierra del Fuego. Quaternary Research 34: 361-371. 2001 Ten Years After: esquema para una tafonomía regional de la Patagonia meridional y norte de Tierra del Fuego. In Desde el País de los Gigantes. Perspectivas Arqueológicas en Patagonia, t. I, edited by S. Espinosa, F. Carballo Marina y J. B. Belardi, pp. 183193. Universidad Nacional de la Patagonia Austral, Río Gallegos. 2011 La función transdisciplinaria de la arqueozoología en el siglo XXI: restos animales y más allá. Antípodas 13: 267-274. Brady, L. M. and R. G. Gunn 2012 Digital Enhancement of Deteriorated and Superimposed Pigment Art: Methods and Case Studies. In A Companion to Rock Art, edited by J. McDonald and P. Veth, pp. 627-643. Wiley-Blackwell, London. Campbell, I. D. 1999 Quaternary pollen taphonomy: examples of differential redeposition and differential preservation. Palaeogeography, Palaeoclimatology, Palaeoecology 149 (1-4): 245–256.

Eren, M. L., A. R. Boehm, B. M. Morgan, R. Anderson and B. Andrews 2011 Flaked Stone Taphonomy: a Controlled Experimental Study of the Effects of Sediment Consolidation on Flake Edge Morphology. Journal of Taphonomy 9 (3): 201-217. Erikson, M. 2012 Tracking Tsunami Flotsam. Natural History 7/8: 18-23. Estevez, J. 2005 Catástrofes en la Prehistoria. Bellaterra, Barcelona. Fernández-Jalvo, Y., L. Scott, J. S. Carrión, G. Gil-Romera, J. Brink, F. Neumann and Ll. Rossouw 2010 Pollen taphonomy of hyaena coprolites: An experimental approach. In Primera Reunión de Científicos sobre Cubiles de Hiena (y otros grandes carnívoros) en los yacimientos arqueológicos de la Península Ibérica, pp. 149-156, Museo Arqueológico Regional, Alcalá de Henares. Fiore, D. and M. L. Varela 2009 Memorias de papel. Una arqueología visual de las fotografías de pueblos originarios fueguinos. Dunken, Buenos Aires.

Clague, J. J. and P. T. Bobrowsky 1994 Evidence for a Large Earthquake and Tsunami 100-400 Years Ago on Western Vancouver Island, B. C. Quaternary Research 41: 176-184.

George, R. 2009 La mayor necesidad. Un paseo por las cloacas del mundo. Turner, Madrid.

Cole, S. C., B. F. Atwater, P. T. McCutcheon, J. K. Stein and E. Hemphill-Haley 1996 Earthquake-induced burial of archaeological sites along the southern Washington coast. Geoarchaeology 11: 165-177.

Gifford, D. P. 1981 Taphonomy and Paleoecology: A Critical Review of Archaeology’s Sister Disciplines. In Advances in Archaeological Method and Theory 4, edited by M. B. Schiffer, pp. 365-438. Academic Press, New York.

Cook, S. F. 1946 A reconsideration of shellmounds with respect to population and nutrition. American Antiquity 12: 50-53.

Gould, R. and M. B. Schiffer 1981 Modern Material Culture: The Archaeology of Us. Academic Press, New York.

Coumont, M-P, C. Thiébaut and A. Averbouh 2010 Integrated Taphonomic Approaches: Review and Perspectives. In Mise en commun des approches en taphonomie. Actes du workshop no 16 - XVe congrès international de l’UISPP, Lisbonne. Paleo - Supplément 3: 133-134. Dominguez-Rodrigo, M. 2012 Conceptual Premises in experimental design and their bearing on the use of analogy: A critical examination from experiments on cut-marks. In. Stone Tools and Fossil Bones, edited by M. DominguezRodrigo, pp. 47-79, Cambridge University Press, Cambridge. Domínguez-Rodrigo, M., S. Fernández-López and L. Alcalá 2011 How Can Taphonomy Be Defined in the XXI Century? Journal of Taphonomy 9 (1): 1-13.

Hayashida, F. M. 2005 Archaeology, Ecological History, and Conservation. Annual Review of Anthropology 34: 43-65. Heyerdahl, T. 1972 The Ra Expeditions. Signet, New York. Hiscock, P. 1985 The need for a taphonomic perspective in stone artefact analysis. Queensland Archaeological Research 2: 82-95. Humes, E. 2013 Garbology. Our Dirty Love Affair with Trash. Avery, New York. Hutchinson, I. and A. D. McMillan 1997 Archaeological evidence for village abandonment associated with late Holocene earthquakes at the northern Cascadia subduction zone. Quaternary Research 48: 79-87.

Multi-service taphonomy. Shells, garbage, and floating palimpsests Lipps, J. 2008 Taphonomy of Oil. Paleontologia Electronica 11 (2), http://palaeo-electronica.org/2008_2/commentary/ oil.htm (Accesed February 2, 2014). Lyman, R. L. 2010 What Taphonomy Is, What it Isn’t, and Why Taphonomists Should Care about the Difference. Journal of Taphonomy 8 (1): 1-16. Meehan, B. 1982 Shell Bed to Shell Midden. Australian Institute of Aboriginal Studies, Canberra. Ministry of Environment 2012 What to do if you find tsunami debris, British Columbia, Canada. Murray, P. 1980 Discard Location: The ethnographic data. American Antiquity 45: 490-502. NOAA Marine Debris Program 2011 Frequently Asked Questions: Japan Tsunami Marine Debris. National Oceanic and Atmospheric Administration, Silver Spring. Odling-Smee, F. J., K. N. Laland and M. W. Feldman 2003 Niche Construction. The neglected process in evolution. Princeton University Press, Princeton. Petraglia, M. D. and D. T. Nash 1987 The impact of fluvial processes on experimental sites. In Natural Formation Processes and the Archaeological Record, edited by D. T. Nash and M. D. Petraglia, pp. 108-130. BAR International Series 352, Archaeopress, Oxford. Pickering, T. R. and C. P. Egerland 2006 Experimental patterns of hammerstone percussion damage on bones: implications for inferences of carcass processing by humans. Journal of Archaeological Science 33: 459-469. Pilarczyk, J. E. and E. G. Reinhardt 2012 Testing foraminiferal taphonomy as a tsunami indicator in a shallow arid system lagoon: Sur, Sultanate of Oman. Marine Geology 295-298: 128-136. Rathje, W. and C. Murphy 1992 Rubbish! The Archaeology of Garbage. Harper Perennial, New York. Ratto, N. and D. Carniglia 2013 Propiedades del registro y tafonomía de conjuntos líticos: el caso del norte de la Provincia de Santa Cruz (Argentina). In Tendencias teórico-metodológicas y casos de estudio en la arqueología de la Patagonia, edited by A. F. Zangrando, R. Barberena, A. Gil, G. Neme, M. Giardina, L. Luna, C. Otaola, S. Paulides, L. Salgán and A. Tívoli, pp. 485-494. Museo de Historia Natural de San Rafael, San Rafael.

19

Renfrew, C. 1979 The Eruption of Thera and Minoan Crete. In Volcanic Activity and Human Ecology, edited by P. D. Sheets and D. K. Grayson, pp. 565-585. Academic Press, New York. Rick, T. C. and J. M. Erlandson (editors) 2008 Human impacts on Ancient Marine Ecosystems. A Global Perspective. University of California Press, Berkeley. Ritter, M. do N., F. Erthal and J. C. Coimbra 2013 Taphonomic signatures in molluscan fossil assemblages from the Holocene lagoon system in the northern part of the coastal plain, Rio Grande do Sul State, Brazil. Quaternary International 305: 5-14. Rodríguez-Vidal, J., L. M. Cáceres, M. Abad, F. Ruiz, M. L. González-Regalado, C. Finlayson, G. Finlayson, D. Fa, J. M. Rodríguez-Llanes and G. Bailey. 2011 The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast. Journal of Iberian Geology 37 (2) 2011: 177-193. Schiffer, M. B. 1976 Behavioral Archeology. Academic Press, New York 1987 Formation Processes of the Archaeological Record. University of New Mexico Press, Albuquerque. Schiffer, M. B. and A. R. Miller 1999 The Material Life of Human Beings. Artifacts, Behavior, and Communication. Routledge, London. Solari, M. E. 1992 Anthracologie et ethnoarchéologie dans l’archipel du cap Horn. Chili. Bulletin de la Société Botanique Francaise 139: 407-419. Spiske, M., J. Piepenbreier, C. Benavente, A. Kunz, H. Bahlburg and J. Steffahn 2013 Historical tsunami deposits in Peru: Sedimentology, inverse modeling and optically stimulated luminescence dating. Quaternary International 305: 31-44. Thiébaut, C., M-P. Coumont, and A. Averbouh 2010 The Taphonomic Approach: an Archaeological Necessity. Mise en commun des approches en taphonomie. Actes du workshop no 16 - XVe Congrès International de l’UISPP, Lisbonne. Paleo - Supplément 3: 21-28. Trigger, B. G. 1989 A History of Archaeological Thought. Cambridge University Press, Cambridge. United Nations Environment Programme 2012 Managing post-disaster debris: the Japan experience. United Nations, Geneva. Urrutia de Habun, R. and C. Lanza Lezcano 1993 Catástrofes en Chile 1541-1992. La Noria, Santiago de Chile.

20

L. A. Borrero - Intersecciones en Antropología - Special Issue 1 (2014) 13-20

VanDerwarker, A. M. and T. M. Peres (editors) 2013 Integrating Zooarchaeology and Paleoethnobotany. A Consideration of Issues, Methods, and Cases. Springer Verlag, New York. Weberman, A. J. 1980 My Life in Garbology. Stonehill Press, New York. Weisman, A. 2007 The World Without Us. Picador, New York.

NOTES 1.- The archaeological study of modern refuse. Such a study is archaeological in the sense that “past” denotes any amount of elapsed time, from a millisecond to a million years or more” (Schiffer and Miller 1999: 52). Not all archaeologists agree that the study of ongoing cultural systems is archaeological (Trigger 1989: 371). Nonetheless, there are strong methodological reasons to maintain not only its relevance for the understanding of the deep past, but also its archaeological character per se (Gould and Schiffer 1981).

|

21

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) Heidi Hammond Received 20 August 2013. Accepted 26 March 2014 ABSTRACT This paper proposes a method of studying archaeomalacological assemblages from shell middens, and describes an application of this method in the analysis of remains recovered from systematic excavations at sites located south of the Ría Deseado estuary (northern coast of Santa Cruz Province, Argentina). This methodology aims to isolate taphonomic variables affecting archaeomalacological records to aid identification of the agents and processes involved in shell midden formation and to improve interpretations of the human activities performed at the sites. These analyses are also relevant to paleoenvironmental and paleoecological reconstructions, and to interpretations of site variability through assessments of assemblage integrity and structure. Keywords: Archaeolomalacology; Taphonomy; Shell middens; Formation Processes; Northern Coast of Santa Cruz.

RESUMEN ANÁLISIS TAFONÓMICOS DE CONJUNTOS ARQUEOMALACOLÓGICOS: CONCHEROS EN LA COSTA NORTE DE SANTA CRUZ (PATAGONIA, ARGENTINA). En este trabajo se presenta una propuesta metodológica para el estudio de conjuntos arqueomalacológicos de concheros y su aplicación en el análisis de restos recuperados a partir de excavaciones sistemáticas en sitios ubicados al sur de la ría Deseado, en la costa norte de Santa Cruz, Patagonia argentina. Esta metodología se focaliza en el estudio de diferentes variables tafonómicas que afectan el registro arqueomalacológico para avanzar en la interpretación de los agentes y procesos involucrados en la formación de las estructuras de concheros y sobre las actividades humanas desarrolladas en los sitios. Además estos análisis son significativos para realizar interpretaciones paleoambientales, paleoecológicas, así como para evaluar la integridad de los conjuntos, interpretar las características estructurales y la variabilidad de los sitios. Palabras clave: Arqueomalacología; Tafonomía; Concheros; Procesos de formación; Costa norte de Santa Cruz.

INTRODUCTION Studies on the northern coast of Santa Cruz Province, Argentina (hereafter NCSC; Figure 1) identified a large number of shell middens distributed along the coast, near the present-day shoreline. Shell middens are located on geomorphological features in areas where food resources such as molluscs and pinniped colonies are abundant (Zubimendi et al. 2005). Shell middens are composed of different archaeological materials in a sedimentary matrix: animal bones (seals, seabirds, fish, and terrestrial mammals, among others), lithic artifacts, charcoal and, primarily, mollusc shells. The

shells’ calcareous composition affords them high preservation potential (Waselkov 1987; Orquera and Piana 1999; Aguirre et al. 2009). The study of taphonomic modifications to mollusc shells can provide information about past human activities and formation processes at archaeological sites, as well as paleoenvironmental and paleoecological conditions (Kidwell 1991; Claassen 1998; Aguirre et al. 2011). As such identification of taphonomic variables can clarify the natural and anthropic process that affected archaeological assemblages (Fernández López 1999; Gutiérrez Zugasti 2008).

Heidi Hammond. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). División Arqueología, Laboratorio 1, Museo de Ciencias Naturales, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. Paseo del Bosque S/N (1900), La Plata. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 21-34. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

22

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

the west and are strongest during the summer months. Vegetation is of the Patagonian Province of the Andean-Patagonian domain and characterized by shrub steppes composed of grasses and coirones (Stipa humilius and S. speciosa) and interrupted by patches of mata negra shrubs (Verbena tridens). Geomorphologically, the San Jorge gulf consists of wide sand or boulder beaches, and rocky tidal flats where mollusc shoals (restingas) develop. To the south of the Cabo Blanco area, the Atlantic coast extends to the Ría Deseado estuary and is characterized by beaches and small intertidal zones with some mollusc shoals. The area south of Ría Deseado is geomorphologically variable with large sand and Figure 1. Northern coast of Santa Cruz Province and archaeological locations boulder beaches interspersed with mentioned in the text. porphyritic outcrops of the Bahía Laura Formation. Mollusc shoals The aim of this paper is to present a methodology develop in this area and species of edible molluscs for the study of archaeomalacological assemblages. belonging to the Magellanic Biogeographic Province The focus is on identification of taphonomic processes are available. that affect archaeological shells and the method is Archaeological materials from sites located offered as a preliminary approach to assessing both south of Ría Deseado are used here as case studies. the integrity of shell middens and the formation Archaeological records in this area indicate intensive processes associated with these features within the but uneven use by hunter-gatherer populations. Major study area. Additionally, results of analyses of three concentrations of archaeological materials are found in archaeomalacological assemblages provide a test areas where animal resource availability −particularly case for the proposed methodology. The assemblages marine resources− tends to be high (Zubimendi et al. were recovered from three archaeological localities on the NCSC: Puerto Jenkins −Puerto Jenkins 2 site (PJ2)−, Bahía del Oso Marino −Las Hormigas site (LH)−, and Isla Lobos −112 site (S112)− (Figure 2).

STUDY AREA The NCSC study area comprises approximately 420 km of coastline, bounded to the north by the boundary between Chubut and Santa Cruz Provinces, and to the south by the Bahía Laura archaeological locality (Castro et al. 2003). The area is characterized by an arid to semiarid climate with average temperatures between 4 °C and 17 °C, and average precipitation of 200 mm, falling largely as winter rain. Predominant winds are from

Figure 2. Archaeological sites mentioned in the text.

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) 2005), as in the Isla Lobos, Bahía del Oso Marino, and Punta Medanosa areas (Figure 2).

SHELL MIDDENS Table 1 provides a contextual description of the shell middens analyzed in this paper. PJ2 is located in the Puerto Jenkins archaeological locality (Figure 2) where numerous shell middens are concentrated near identified mollusc shoals. Middens are found up to 400 m from the modern shoreline (Zubimendi et al. 2004). PJ2, dated to 690 ± 60 years BP, is located 100 m from the Ría Deseado shoreline. LH is located in the Bahía del Oso Marino locality, where shell middens are heterogeneously distributed (Zilio and Hammond 2013). The site is radiocarbon dated to 370 ± 40 years BP and located at 16 masl and 80 m from the present coastline. S112 is located in the Isla Lobos archaeological locality (Castro et al. 2003), where shell middens cluster near the coastline. S112 is located 100 m away from the current shoreline and 11 masl. Fragments of charcoal associated with archaeological materials date to 2870 ± 60 years BP (Table 1).

MATERIALS AND METHODS Excavation On the NCSC, shell middens are composed of very thick lenses of archaeological materials, so excavations proceeded in 5-cm artificial levels. According to Bejega García (2010), stratigraphic differences between massive levels of mollusc shells may be based on biological composition where the presence or absence of particular species defines the stratigraphy. Therefore, excavating by artificial levels aids detection of differences in high-density shell lenses that may not be identified otherwise. Recovery of small items was performed using a 2 mm mesh sieve (Claassen 1998), and the “bottom sieve” −the smallest items remaining after sieving− was collected for classification and further analysis in the laboratory (Bowdler 2009). The following section details the methodology for identification, classification, and quantification of mollusc shells. It also describes different taphonomic agents (Lyman Archaeological 1994) and lists Archaeological site locality selected taphonomic Puerto variables that should Puerto Jenkins 2 Jenkins be considered in −PJ2− any taphonomic Las Hormigas Bahía del Oso approach to −LH− Marino archaeomalacological Site 112 Isla Lobos assemblages. −S112−

23

Mollusc shell analyses: identification, classification and quantification 1. Anatomical and taxonomic identification and quantification of archaeological shellfish assemblages In archaeological shellfish assemblages, anatomical and taxonomic identification is based firstly on distinctive features of the shells, such as morphology, color, sculpture and decoration; and secondly on biogeographical distributions. Once a shell has been identified anatomically, taxonomic identification proceeds using diagnostic features that permit assignment, ideally to the species level (Gutiérrez Zugasti 2008). Taxonomic features used in the identification of the molluscs are: (for gastropods) shape of the shell, characteristics of the umbilicus and aperture, and characteristics of ornamentation; (for bivalves) shape of the shell, hinge features, number and arrangement of muscular impressions, and ornamentation (Moreno Nuño 1994: 16); and (for polyplacophorans) shape of the shell and ornamentation (Gordillo 2007). Shells are grouped into categories according to their preservation: • Complete shells (VCOM) are those exhibiting more than 90% of the original shell and an individual diagnostic element, known as a Non-Repetitive Element (NRE; Mason et al. 1998). An NRE is a part of a shell that is diagnostic for each species or genus, which can be counted a number of times to infer the presence of an individual. In gastropods, NRE include the apex, columella, and foramen. In bivalves, it is the hinge or the umbo, to be differentiated right from left. Polyplacophorans (chitons) are composed of eight plates, one cephalic, one caudal, and six intermediate; individuals can be counted taking the highest value of cephalic or caudal plates. On complete shells, biometric measurements are made, including length, width, and height of the shell. • Diagnostic shell fragments (VFRA) are shells less than 90% complete but that still contain an NRE. Gastropod fragments were assigned to one of two categories.1) IFRA are fragments with intact columella ends but that lack the buccal area. Among Nacella magellanica, IFRA contain the apex and part of the shell. 2) FAPI are fragments that include apex or portions of it. On bivalves the identifiable fragments were subdivided into: VFRA (fragmented shell) and FCHC (fragment of umbo or hinge complete) (Álvarez Fernández 2007).

Age 14C (years BP)

Location

370 ± 40 (LP-2504)

cord of coastal boulders with sandy cover burdensome aeolian mantle on Holocene terrace

2870 ± 60 (LP-2141)

Aeolian mantle

690 ± 60 (LP-2603)

Table 1. Description of archaeological sites presented in this paper.  

Excavated área (m2)

Stratigraphic thickness (cm)

0.5

43

1

55

0.25

17

24

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

• Fragments (FRAG) are pieces of shell that lack diagnostic elements. Fragments can contribute to measures of abundance including NISP, the number of identifiable specimens (complete shells plus fragments), and MNI, the minimum number of individuals for each genus or species. For gastropods, MNI is calculated according to the formula: VCOM + FAPI + IFRA. For bivalves, MNI is calculated as VCOM + FCHC + VFRA (taking the highest value between left and right VFRA; Álvarez Fernández 2007). Fragments are also used to calculate taxonomic richness, defined as the total number of taxa in a collection. Assemblage diversity is the number of individuals (NISP or NMI) distributed across all the identified species or taxa (Claassen 1998; Dupont 2003).

In the NCSC contexts analyzed to date, we have identified three groups of molluscs −gastropods, bivalves, and polyplacophorans− using specific literature (Castellanos 1970; Aguirre 2003; Aguirre et al. 2009 and Gordillo 2007 for polyplacophora, among others), and a comparative collection consisting of both modern and archaeological specimens (Bejega García 2010), and following the nomenclature of the World Register Marine Species (WoRMS 2012) database.

2000; Glassow 2000). Claassen (1998: 107) points out that criticisms of shell weight quantification center primarily on the loss of weight with diagenesis, which affects different species at different rates. The author notes that the older the site or the more acidic the soil, the greater the loss of calcium carbonate and conchiolin and the greater the differential loss of calcium carbonate between species. Álvarez Fernández (2007) indicates that we must consider that different taphonomic agents and processes that could affect archaeomalacological remains and the weight of shells, such as descaling or precipitation of calcium carbonate and matrix acidity. Moreover, Bejega García (2008) notes that despite the limitations of weight for estimating abundance, weight values are ​​ still important as they may reflect changes in the shell composition of archaeological levels within a site. In the same way, if a sample is highly fragmented, weight is sometimes the only available criterion of analysis.

Taphonomic agents and taphonomic processes 1. Taphonomic agents

2. Biometric analysis Following taxonomic identification of archaeomalacological assemblages, biometric analysis (length, width, and height) of complete shells is required. Shell size is related to the age of the individual, the microenvironment in which it developed, and ontogenetic growth rate, which decreases as age increases (Claassen 1998). At NCSC shell middens, the most abundant conchological species are Nacella magellanica (limpet), Aulacomya atra (ribbed mussel), Mytilus edulis (blue mussel), and Perumytilus purpuratus (Zubimendi et al. 2005; Zubimendi 2012; Hammond and Zubimendi 2013). To gauge shell size, the maximum diameter of the base of the shell is measured in Nacella magellanica; in bivalves, maximum diameter is measured from the umbo to the distal end of the shell. Usually, biometric analyses are used to interpret the processes of overexploitation, in studies of growth environments, for estimating season of harvest (Claassen 1998), and to determine whether there may have been size selection during harvesting (Álvarez Fernández 2009). Occasionally these analyses have also been used to explore the mode of harvest, estimate the size of the sampled population, and identify rare or uncommon species at archaeological sites (Claassen 1998).

3. Weight of the remains The weight of archaeomalacological assemblages is a variable that has been widely discussed by many authors (Claassen 1998, 2000; Mason et al. 1998,

A taphonomic agent is a source of force applied to materials, and the physical cause of modification (Morlan 1984; Lyman 1994). Archaeological materials have their own taphonomic histories, and it is necessary to identify the agents and processes responsible for any signs of modification. Agents that modify materials in the archaeological record have predictable physical effects (Schiffer 1983) that can be inferred (Nash and Petraglia 1987). In this way, taphonomic studies in archaeology contribute to our understanding of the formation of archaeological sites (Borrero 1988). A variety of taphonomic agents alter the remains that compose shell middens: • Biological: Fauna (both vertebrates and invertebrates) and flora are considered among biological agents. At NCSC, fossorial rodents (Ctenomys sp.), Magellanic penguins (Spheniscus magellanicus), and armadillos (Zaedyus pichiy and Chaetophractus villosus) are among the animals that modify remains and their spatial arrangements in shell middens by moving and scattering archaeological material. These animals can also introduce foreign remains through the caves they excavate (Hammond et al. 2013). The modern introduction of livestock (sheep) is another factor that disturbs shell middens; trampling causes the removal, displacement, and fragmentation of archaeological remains. Vegetation may also cause movement and mixing of archaeological remains, and root growth in fissures or cracks may fracture shells, all of which can mechanically change the original structure of deposits. Roots between the shells can also trigger chemical dissolution (Gutiérrez Zugasti 2008). • Anthropic: Human populations can modifiy the archaeological record in several ways, whether deliberately or accidentally. Such modifications can

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) be divided into ones produced during occupation of the site and those that occur after abandonment. For example, trampling of archaeomalacological remains post-deposition can cause considerable fragmentation and horizontal displacement. Subsequent reoccupation of archaeological sites can further modify preexisting structures. Excavation by non-specialists, construction of roads, urban growth, and the use of vehicles in coastal areas are also agents of archaeological site destruction (Ceci 1984; Zubimendi et al. 2012). • Physical-geological: The primary physical agents affecting shell middens are water and wind. In open-air shell middens, fluvial processes and wind can transport archaeological remains, resulting in the modification of site morphology and structure. Wind erosion, storms, and sudden changes in temperature can accelerate the degradation, fragmentation, and mobilization of the shells (Claassen 1998). Moisture and sunlight are other agents that may alter the remains. • Chemicals: Archaeological remains can be chemically altered according to chemical conditions within the sedimentary matrix. A variety of variables, including pH and the relative proportion of organic matter, phosphate, carbonate and salt, can be studied to assess conservation, pollution, and other chemical processes that affect assemblages. The pH level of the matrix affects the preservation of certain archaeological remains. Stein (1987) suggests that soil pH is affected by the amount of organic waste introduced by people during site occupation. Generally, an abundance of calcium carbonate, of which shells are composed, causes a neutral or slightly alkaline pH, which tends to preserve many organic remains (Orquera and Piana 2000). However, a highly alkaline environment creates unfavorable conditions for the preservation of organic remains such as bone because it induces collagen hydrolysis (Favier Dubois and Bonomo 2008). High salinity and high levels of organic matter within the midden matrix cause a higher incidence of corrosion.

25

they have undergone throughout the formation of the archaeological deposit.

Taphonomic variables •Preservation of periostracum: The periostracum is an outer membrane composed of protein that covers the shells of some gastropods and bivalve molluscs (Figure 3A). This membrane is especially visible in the shells of species within the family Mitilidae, particularly Aulacomya atra and Mytilus edulis. This organic layer is secreted by a mantle portion of molluscs, and its main function is to protect the limestone part of the shell against various hazards including acidic substances (Camacho 2007). Preservation of the periostracum on archaeological shells is interpreted as a sign of the record’s integrity and of rapid burial (Zubimendi 2012; Hammond and Zubimendi 2013). Preservation of this membrane in stratigraphic contexts is also determined by conditions within the sedimentary matrix (moisture, organic content, and pH). Under unfavorable conditions of burial, periostracum loss will progress through time. When exposed to environmental conditions (wind, sun, rain, and moisture) the periostracum dries quickly, fractures and falls off easily. The preservation of periostracum is recorded as present (1) or absent (0).

2. Taphonomic processes on shells People and animals are geomorphological agents that produce archaeological sediments, the physical, biogenic, and cultural components of which require identification and interpretation (Butzer 1982: 66). Thus, shell accumulations are considered archaeosediments (Butzer 1982; Stein 1987). The identification of natural and anthropic components is therefore critical to the interpretation of formation processes at archaeological sites. For this reason, analysis of taphonomic processes that have affected archaeological remains is a means of understanding their origins and the changes

Figure 3. A. Aulacomya atra shells with preserved periostraca; B. Shells with evidence of surface corrosion; C. Shells with evidence of surface abrasion.

26

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

•Corrosion: Corrosion occurs when calcium carbonate −in the form of calcite or aragonite (Camacho 2007)− or other mineral components of the shell dissolve due to chemical conditions in the environment (Gutiérrez Zugasti 2008; Figure 3B). Chemical erosion first attacks thinner surface areas, which leads to characteristic shapes on particular taxa. Some effects of chemical dissolution of shells are a corroded appearance of surfaces, loss of ornamentation, and thinning and development of holes and cracks (Fernández López 1999: 81). Identification of such alterations can indicate the environmental conditions in the organism’s habitat or deposition matrix. Moreover, corrosion can be inferred from analyses of the substrate where the remains were deposited. Corrosion and dissolution of shells’ mineral components are greater in areas where salinity is high, temperatures are low, and bioturbation is common (Claassen 1998: 59). Chemical dissolution is also related to sediment moisture conditions, climatic fluctuations, and the abundance of vegetation in the substrate (Aguirre et al. 2011). Corrosion is recorded as present (1) or absent (0). •Abrasion: Abrasion refers to the removal of calcium carbonate, of which shells are composed, by physical processes or bioerosion (Claassen 1998). This process leads to weathering of shells’ most prominent exterior ornamentation, modifying their original texture and creating porous surfaces (Figure 3C). Corrasion is abrasion caused by wind (Breed et al. 1997) and its effects vary according to wind speed, hardness of the abraded surface, concentration of abrasive particles (such as sand), and the density and distribution of vegetation and topographic features (Waters 1992).Time of exposure on the land surface is also a factor. Abrasion analysis can provide information regarding sedimentation at the archaeological site, displacement of archaeological remains, and postdepositional processes. It is important to assess abrasion to identify which remains were incorporated in to the site by people, and which by natural processes. For example, small gastropods that form natural coastal cords where archaeological sites are sometimes located generally have evidence of marine abrasion and can be integrated as part of the sedimentary matrix of sites. Shell abrasion is recorded as present (1) or absent (0). •Deformation: Deformation refers to changes in the size, shape, structure, and/or texture of shells due to mechanical stress. This process may cause folds, fissures, cracks, or fractures. Sediment pressure may cause deformation of overall shape (Álvarez Fernández 2009). This process is enhanced if the sediment column has high levels of moisture or organic material, which affect the microstructure of the shell and its resistance (Zuschin et al. 2003). At NCSC, deformation has been observed mainly on limpet shells. •Fragmentation: Fragmentation is one of the most common processes observed in archaeomalacological assemblages and involves breakage of shells and separation of the fragments. This process can affect anatomic and taxonomic identification of the remains (Gutiérrez Zugasti 2008). Shells, particularly those of bivalves, tend to fragment along existing features, such as growth and ornamentation lines (Farinati and Zavala 1995). Fragmentation will vary according to the morphology, microstructure, thickness,

ornamentation, size and strength of the shell, as well as biostratinomic processes (Claassen 1998; Aguirre et al. 2011). Other factors that may affect the structure of shells and increase fragmentation of an assemblage are exposure to heat (Claassen 1998), decalcification and biodegradation (Gutiérrez Zugasti 2008), and the amount of organic matter and moisture in the sedimentary matrix (Zuschin et al. 2003). Sedimentary processes such as compression (Claassen 1998), and biological (e.g., bioturbation and root action) and natural processes (e.g., effects of water, wind and temperature fluctuations) may also influence increase fragmentation rates. Fragmentation increases the susceptibility of the particles to size sorting and transport by different agents (Claassen 1998: 55). Different anthropic processes can produce fragmentation such as trampling, site cleaning (removal of remains), production of artifacts or instruments, or the mode of shellfish gathering. •Thermal alteration: Heat alters the crystallographic structure of shells. The higher the temperatures they are exposed to, the faster they will deteriorate and, ultimately, break. Shells affected by thermal exposure experience changes in the original color of the surface and weight loss relative to unburned shells (Claassen 1998). For example, limpets that have not been affected by heat are brown whereas those exposed to high temperatures for longer periods are dark gray, often carbonized, and their structure is very weak, which causes them to be easily fragmented (Claassen 1998; Villamarzo 2009), thereby affecting conservation of the entire assemblage. Carbonification is related to the exposure of shells directly to flames, and involves carbon enrichment. Typically, molluscs are covered by a layer of very fine gray sediments (Gutiérrez Zugasti 2008). Thermal alteration of shells is determined by macroscopic appearance and color and recorded as not burned (0, original color); burned (1, light brown-gray); carbonized (2, dark brown to black color); or calcined (3, white color) (Villamarzo 2009; Villagran et al. 2010). •Breakage and/or deliberated impact of shells: It has been suggested that breakage and/or impact on shells may be related to the way some species of molluscs were harvested (Pailler et al. 2007). In particular shell middens at NCSC, many limpet shells are cracked or broken (Figure 4A). These breaks may be due to the use of an instrument to release the molluscs from the rocks where they grow. When a hard blow is delivered to detach a shell, breaks along the margin or side may occur. Classification and recording of impacts and breakage follows Pailler and colleagues (2007). These authors divide shells of the gastropod Nacella magellanica into eight zones and in three areas in relation to the height of the shell (Figure 4B). By this method, the location of impacts / breakage can be recorded in a way that permits comparison. •Bioerosion: The analysis of bioerosion can provide paleoecological information. Many marine organisms are capable of eroding and modifying shells, for predatory reasons or otherwise (Figure 5). Algae, fungi, foraminifera, bryozoans, bivalves, gastropods, sponges, and barnacles can cause such modifications before and/or after death of the shellfish (Claassen 1998). Some gastropods, particularly

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina)

27

embedded on shells collected by human groups. In the archaeomalacological assemblages of the NCSC, Balanus sp. is the predominant encrusting species (Hammond and Zubimendi 2013). Sometimes the encrustations occur on the inner surface of the shells, which indicates that they were incorporated into the archaeological record after the death of the organism. The presence of encrustations or epibiont organisms can prevent the effects of bioeroders on shell surfaces (Claassen 1998: 40). •Color preservation: This variable is recorded as an indicator of preservation of the remains. The preservation of color depends primarily on the chemical composition and stability of the pigment that colors the surface, and the mineralogical composition of shell (Claassen 1998). Color loss is determined by different agents. It is important to distinguish the processes involved and their effects because different processes can have similar effects (Lyman 1994: 38). Abrasion, corrosion, and thermal alteration are the main taphonomic processes related to the loss of original shell color, and can significantly affect the surface coloration and ornamentation. Color loss due to sunlight exposure causes shells to acquire Figure 4. A. Shells with evidence of impacts and breaks; B. Segmentation of a white color superficially. Preservation of shells to record the position of impacts and breaks. original shell color was recorded using the following scale: conservation of the original color (0); naticid and muricid, drill shells with their radula leaving partial conservation of the original color (1); total loss circular holes with slightly tapered or straight sides (Álvarez of original color (2); total color loss by sun exposure Fernández 2009). The holes produced by mollusc drilling (3) (Figure 6). can result in either complete perforation or incomplete, “unsuccessful” perforation. Perforations are made in exposed or weak areas of shells; among bivalves, this is usually near the umbo, and among gastropods, near the apex. Drilling facilitates future fracture of shells (Claassen 1998; Zuschin et al. 2003). Completely perforated shells likely entered the deposits dead because of the action of bioeroding organisms to obtain soft tissue or calcium. Sometimes mollusc shells have other epibiont organisms attached to them. Such organisms erode and remove the periostracum, and produce erosion and surface marks. Heavy encrustation occurs on dead organisms’ shells exposed at the water–sediment interface in low energy habitats (Claassen 1998). It is important to identify these types of marks to avoid confusion with marks produced by humans. Bioerosion studies allow understanding the presence of certain species in the malacological assemblage, which could be incorporated to the site Figure 5. Shells with surface bioerosion.

28

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34 shells were recorded in LH and S112, and imbricated limpet shells were recorded in situ at PJ2. These features indicate rapid burial without mobilization of the archaeological remains.

Malacological composition of shell middens Table 3 presents mollusc species NISPs and MNIs for each excavation. Twenty-three species were identified, and some specimens remain unidentified. Most of the species are gastropods and Nacella magellanica is the predominant species in all assemblages. The remaining gastropod species occur in smaller amounts. Of the bivalves, Mytilus edulis, Aulacomya atra and Perumytilus purpuratus predominate; the rest of the species are represented by a few specimens each. Regarding species richness, LH has the highest conchological diversity, while S112 exhibits

Figure 6. Degrees of color preservation of shells.

Table 2 presents a characterization of shells identified in each of the middens analyzed in terms of the variables proposed by Favier Dubois and Borella (2007), Zubimendi (2012), and Hammond and Zubimendi (2013). Excavations profiles are presented in Figure 7. Shell middens are located on different geomorphic surfaces: lines of coastal boulders with sandy cover and sandy aeolian mantles. The shell concentration at the PJ2 site is described as having tabular stratigraphic geometry with a high density of shells in contact with each other (bioclast-supported structure). The LH and S112 sites are described as having lenticular geometry affected by erosion and deflation that has exposed the surfaces of archaeological remains. These processes generated mound-shaped accumulations formed by a surface layer of shells redeposited above aeolian sediments that compose the dunes (Hammond et al. 2013). In all three case studies, individual lenses with high-density archaeological remains were identified in the stratigraphic sequence. The surfaces on which the sites are located are horizontal to subhorizontal. During excavations, articulated mussel

Concentrations of shells

RESULTS Variables analyzed Thickness Location Geometry Estratigraphy Orientation

Tilt Shells articulated in situ

Puerto Jenkins 2 15 cm sandy cover burdensome Tabular 1 lens of shells No preferential orientation Subhorizontal Yes

Las Hormigas 8 cm

Site 112 6 cm

aeolian mantle

aeolian mantle

Lenticular 1 lens of shells No preferential orientation Subhorizontal

Lenticular 1 lens of shells No preferential orientation Subhorizontal

Yes

Yes

Table 2. Features of shells concentrations at the shell middens.

Figure 7. Excavations profiles.

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina)

Puerto Jenkins 2

Mollusc

Site 112

Las Hormigas

NISP

MNI

NISP

MNI

NISP

MNI

2440

2440 (69.2%)

509

509 (18.85%)

35

35 (5.8%)

94

94 (2.66%)

72

72 (2.7%)

4

4 (0.7%)

2

2 (0.05%)

7

7 (0.25%)

2

2 (0.35%)

2

2 (0.05%)

5

5 (0.2%)

-

-

-

-

2

2 (0.07%)

-

-

1

1 (0.02%)

-

-

-

-

-

-

1

1 (0.04%)

-

-

5

5 (0.14%)

12

12 (0.45%)

7

7 (1.16%)

5

5 (0.14%)

11

11 (0.4%)

-

-

-

-

1

1 (0.04%)

-

-

31

31 (0.9%)

9

9 (0.35%)

9

9 (1.5%)

-

-

1

1 (0.04%)

-

-

Gasteropodoindet.

3

3 (0.08%)

10

10 (0.35%)

-

-

Cl. Bivalvia

NISP

MMI

NISP

MNI

NISP

MNI

Cl. Gasteropoda Nacella magellanica Crepipatella dilatata Pareuthria plumbea Trophon geversianus Buccinanops globosum Adelomelon sp. Epitonium magellanicum Siphonaria lessoni Fissurella sp. Acantina monodon Kerguelenella lateralis Iothia coppingeri

Mytilusedulis

1390

726 (20.6%)

1462

761 (28.2%)

941

488 (81%)

Aulacomyaatra

164

101 (2.9%)

1658

873 (32.5%)

10

6 (1%)

Perumytilus purpuratus

207

114 (3.2%)

709

389 (14.4%)

82

50 (8.3%)

Ensis macha

-

-

17

11 (0.4%)

1

1 (0.16%)

Hiatella solida

1

1 (0.02%)

3

2 (0.07%)

-

-

Hiatellaartica

-

-

1

1 (0.04%)

-

-

Taweraelliptica

1

1 (0.02%)

18

11 (0.4%)

-

-

-

-

1

1 (0.04%)

-

-

Petricolaria patagonica Darina solenoides

29

uneven at our study sites (Table 5). The main processes that have affected the shells in these assemblages are fragmentation, corrosion, and thermal alteration. Regarding shell color preservation at LH, a very low percentage of the specimens retain their original color (2.2%) and more than half of the assemblage reflects a partial loss of original shell color (68.9%). In the PJ2 and S112 assemblages, almost all of the shells have completely lost their original color, possibly due to high levels of thermal alteration and corrosion. The total loss of color by sun exposure is very low at LH, and was observed primarily among remains exposed on the surface. At LH, a high percentage of shells (primarily Aulacomya atra) retain their periostraca, which may indicate rapid burial and a high-integrity record (Zubimendi and Hammond 2009; Zubimendi 2012; Hammond and Zubimendi 2013).

The PJ2 assemblage has a high incidence of corrosion (99.5%), while the proportion MNI NISP MNI NISP MNI NISP Cl. Polyplacophora of abraded shells is low in all 15 4 (0.14%) Neoloricata of the analyzed assemblages. 9 13 13 18 18 9 Richness Abrasion is evident on shells 602 4347 3527 4529 2698 1091 Total that were exposed on the Table 3. Species of molluscs at the shell middens (NISP and MNI). surface and in contact with particles that abraded and polished surfaces. the minimum value, the latter being both the earliest Thermal alteration among shells from LH, indicate site and the one with the smallest excavated area. that part of the assemblage was exposed to heat. Table 4 presents the weight of the shell remains at However, well-preserved shell structures suggest the each site, sorted by mollusc class and quantification heat exposure may have been of short duration or the category. temperature relatively low. At S112, the malacological remains have been severely affected by thermal Taphonomic alterations of the Weight of the remains of shells (grams) Archaeological shells Mollusc SF. Veneridae

-

-

2

2 (0.07%)

-

-

1

1 (0.02%)

3

3 (0.11%)

-

-

sites

The taphonomic analysis of mollusc shells presented here is preliminary and, accordingly, we focus our analysis of taphonomic processes on complete mollusc shells (VCOM). Preservation of the archaeomalacological remains is

Puerto Jenkins 2 Las Hormigas Site 112

Cl. Gasteropoda Cl. Bivalvia Cl. Polyplacophora Cl. Gasteropoda Cl. Bivalvia Cl. Polyplacophora Cl. Gasteropoda Cl. Bivalvia Cl. Polyplacophora

Table 4. Weight of the remains of shells.

VCOM 13,514 667 0 1,945 4,084 2 237 558 0

VFRA 2,862 3,583 0 191 5089 1 44 2,488 0

FRAG

TOTAL

12,689

33,315

9,615

20,927

2,513

5,840

30

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

Color preservation

Variables analyzed Original color Partial conservation of color Total color loss Total color loss by sun exposure

Periostracum conservation Evidence of corrosion Evidence of abrasion Presenceofencrustations Evidence of bioerosion not burned burned carbonized calcined Breakage and/or deliberate impact on shells of Nacella magellanica Total of mollusc shells (VCOM) on which color and taphonomic variables were calculated

Las Hormigas 39 (2.22%)

Site 112 0 (0%)

70 (3.6%)

1207 (68.9%)

3 (2%)

1877 (96.4%)

489 (27.9%)

175 (98%)

1 (0.1%)

17 (1%)

0 (0%)

1 (0.1%)

1006 (57.4%)

0 (0%)

1939 (99.5%) 6 (0.3%) 5 (0.3%) 11 (0.6%) 0 (0%) 840 (43%) 0 (0%) 1108 (57%)

649 (37.05%) 8 (0.45%) 18 (1.03%) 4 (0.25%) 406 (23%) 1349 (77%) 0 (0%) 0 (0%)

118 (66%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 178 (100%)

and 73.2% of P. purpuratus shells are complete, respectively. Signs of in situ fragmentation of Mytilus edulis and Aulacomya atra shells were observed at LH and S112, which may be the result of trampling and/or sediment compression.

Thermal alteratio n

Unidentifiable fragments (FRAG) represent large volumes of malacological material in the study area. To date, we have used weight to estimate the relative abundance of this type of debris (Table 4). Some authors identify the remains at the level of the species and perform quantification 460 (23.6%) 139 (7.95%) 3 (2%) thereof (Moreno Nuño 1994; Álvarez Fernández 2007; Bejega García 2009). Another approach is assessing the size 1948 1752 178 of fragments to evaluate factors of Table 5. Color preservation and taphonomic processes that have affected the fragmentation and depositional history malacological remains. (Stein 1987; Ford 1992). Such analyses of unidentifiable fragments (FRAG) should be part of alteration. The shell lens was located above a burned future studies designed to more thoroughly investigate layer of sediment, ash and charcoal; the shells’ surfaces the multiplicity of agents and factors that determine are light gray to white (calcined), they have lost the the preservation of shells (Muckle 1985; Ford 1992; original color, and their crystallographic structure has Claassen 1998). been altered and deteriorated. During excavation, shells were easily fractured when removed from the sediment. The PJ2 malacological assemblage was also thermally altered, which accounts for the high percentage of DISCUSSION shells exhibiting total loss of original color, that are The archaeomalacological assemblages presented brown (43% burned) or are light gray to white (57% in this paper correspond to single discard events. The calcined). Also, there is a high percentage of Nacella shells were in contact with one another (bioclastmagellanica shells with impacts or breaks, interpreted supported fabric) at all sites, creating discrete lenses as anthropic alteration due to the irregularity of the of archaeological remains with good integrity. At LH fractures, similarity to other excavated sites, and based and S112, deflation and erosion have exposed the on experimental replication. The proportion of shell archaeological materials, which begin to deteriorate alterations by other marine organisms (encrustation and perforation) is insignificant, and the primary encrusting species recorded at the sites is Balanus sp. Taphonomic variables

 

Puerto Jenkins 2 0 (0 %)

Fragmentation of archaeomalacological assemblages The malacological assemblages analyzed here all have similar percentages of fragmentation: approximately 70% of Nacella magellanica shells are complete (Figure 8), while Mytilus edulis and Aulacomya atra shells are highly fragmented. Mussel shells are best preserved at LH (23% of Mytilus edulis and 30.5% of Aulacomya atra were complete), whereas only 10% of Mytilus edulis and Aulacomya atra shells are complete at S112 (Figure 8). Fragmentation may be influenced by deterioration of the shells due to thermal alteration. Perumytilus purpuratus shells were differentially preserved at the sites. At PJ2, 47.3% of this species is complete; while at LH and S112 71.8%

Figure 8. Percentages of complete (VCOM) and fragmented (VFRA) shells of the main species represented at the sites.

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina) rapidly when subjected to environmental conditions. At PJ2, the archaeological remains are completely buried, and the site surface was covered by vegetation that fixed the surface sedimentary layer and prevented exposure of the archaeological remains. The integrity of the assemblages is good; burial was likely rapid and archaeological materials appear not to have been scattered. This resulted in the formation of massive archaeological deposits, resistant to disaggregation. At all sites the level of abrasion is low, and evidence of abrasion was observed only on shells found in superficial layers, indicating that they were not exposed to environmental conditions (wind, water effect) for long time. The taphonomic processes most evident among the assemblages are fragmentation, corrosion, and thermal alteration, although the malacological remains are generally well preserved. At LH, rapid burial preserved periostraca and original color in high proportions (though it should be noted that this is also the youngest site). Articulated mussel shells were found in situ at the three sites, and imbricated limpet shells were found at PJ2. High percentage of corrosion and thermal alteration were also recorded at PJ2, which led to a high percentage of shells exhibiting loss of original color. At S112, shells were severely altered by heat, which made them very weak; bivalve shells in particular have not preserved periostracum neither the original shell color. Similar trends in fragmentation are observed in all assemblages. Mytilus edulis and Aulacomya atra shells have the highest percentages of fragmentation, while Perumytilus purpuratus and Nacella magellanica have higher percentages of complete shells. This could be due to structural and morphological characteristics of the shells themselves, although it must be recognized that different processes (e.g., corrosion, thermal alteration, sediment pressure) can significantly affect their structure and lead to fragmentation. Study of the NCSC shell middens indicates that mussels usually have higher levels of fragmentation than gastropods such as Nacella magellanica (Zubimendi 2012; Hammond and Zubimendi 2013). Future studies should incorporate analyses of diagnostic or identifiable (VFRA) mollusc shell fragments to obtain more comprehensive information regarding the processes that have affected the archaeological remains. Archaeological remains at all three sites are associated with fragments of charcoal and thermally altered sediments, which suggests that the molluscs may have been exposed to heat for cooking and opening the shells of bivalves. At the three shell middens, we also recovered lithic artifacts and faunal remains (generally highly fragmented) in association with the shell lenses and charcoal (Hammond y Zubimendi 2013).

31

We observed that the predominant taxa in the malacological assemblages are those identified as important foods (Nacella magellanica, Mytilus edulis and Aulacomya atra), which develop on hard substrates in the intertidal zone (Zubimendi et al. 2005). We have also observed low frequencies of various taxa that, because of their small size, cannot be considered as food (for example Crepipatella dilatata, Siphonaria lessoni, Kerguelenella lateralis, Iothia coppinheri or Balanus sp.). These species are important because they provide information about environmental conditions and site formation processes. These small molluscs may have been deposited in the site as an unintentional by product of particular harvesting techniques, such as collecting in bunches (Orquera and Piana 1999).

CONCLUSIONS In this paper, we presented a proposal for the study of shell midden archaeomalacological assemblages, and emphasized the importance of taphonomic studies in the identification of agents that modify shells and processes that affect shell midden formation in the study area. Based on the results of our analyses of malacological assemblages at NCSC, we argue that it is possible to infer the agents (natural and anthropic) and processes (pre- and post-depositational) that have produced physical and/or chemical modifications on the shells. The advantage of our methodological approach to archaeomalacological assemblages is its applicability to different kinds of archaeological records composed of molluscs. Due to their composition, shells are more resistant than other organic remains such as bone (Linse 1992) or wood. Moreover, insights gleaned from the study of archaeomalacological assemblages extends beyond interpreting the records themselves, contributing to discussions of archaeological site formation.

Acknowledgements I would like to thank A. Castro and M. Zubimendi for their comments and suggestions. I also want to thank L. Zilio who made the figures, and the reviewers and editors whose comments on an earlier draft of this paper helped to improve it.

REFERENCES Aguirre, M. 2003 Late Pleistocene and Holocene palaeoenvironments in Golfo San Jorge, Patagonia: molluscan evidence. Marine Geology 194 (1): 3-30.

32

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

Aguirre, M., S. Richiano, M. Álvarez and C. Eastoe 2009 Malacofauna Cuaternaria del litoral norte de Santa Cruz (Patagonia, Argentina). Geobios 42: 411-434. Aguirre M., S. Richiano, E. Farinati and F. Fucks 2011 Taphonomic comparison between two bivalves (Mactra and Brachidontes) from Late Quaternary deposits in northern Argentina: Which intrinsic and extrinsic factors prevail under different palaeoenvironmental conditions? Quaternary International 233: 113-129. Álvarez Fernández, E. 2007 La explotación de los moluscos marinos en la cornisa Cantábrica durante el Gravetiense: primeros datos de los niveles E y F de la Garma A. (Omoño, Cantabria). Zephyrus 60: 43-58. 2009 Análisis arqueomalacológico de la cueva de Altamira (Santillana del Mar, Cantabria): Excavaciones de J. González Echegaray y L. G. Freeman. Complutum 20 (1): 55-70. Bejega García, V. 2008 Composición y metodología de análisis de concheros aplicada a los castros litorales gallegos. In Actas de las I Jornadas de Jóvenes en Investigación Arqueológica: Dialogando con la cultura material, pp. 247-254. Compañía Española de Repografía y Servicios, Madrid. 2009 El aprovechamiento de los recursos marinos en el Castro Grande de O Neixón (Boiro, a Coruña): un análisis arqueomlacológico. Tesina de Licenciatura inédita. Universidad de León, España. 2010 La arqueomalacología: una introducción al estudio de los restos de moluscos recuperados en yacimientos arqueológicos. Iberus 28 (1):1-10. Borrero, L. A. 1988 Estudios tafonómicos en Tierra del Fuego: su relevancia para entender procesos de formación del registro arqueológico. In Arqueología contemporánea argentina. Actualidad y perspectivas, edited by H. Yacobaccio, L. A. Borrero, L. C. García, G. G. Politis, C. A. Aschero and C. Belleli, pp. 13-32. Búsqueda, Buenos Aires. Bowdler, S. 2009 Mollusk and other shells. In Archaeology in practice: A student guide to archaeological analyses, edited by Balme, J. and A. Paterson, pp. 316-337. Wiley-Blackwell, Malden. Breed, C., McCauley and M. Whitney 1997 Wind erosion forms. In Arid zone geomorphology, edited by D. S. G. Thomas, 284-307. Wiley, Londres. Butzer, K. 1982 Archaeology as human ecology. University Press, Cambridge.

Camacho, H. 2007 Los invertebrados fósiles. In Mollusca, edited by H. Camacho and M. Longobucco, pp. 293-322. Fundación de Historia Natural Félix de Azara, Buenos Aires. Castellanos, Z. 1970 Catálogo de los Moluscos marinos bonaerenses. Anales de la Comisión de Investigaciones Científicas 8: 1-365. Castro, A., J. E. Moreno, M. A. Andolfo, R. Giménez, C. Peña, L. Mazzitelli, M. A. Zubimendi and P. Ambrústolo 2003 Análisis distribucionales en la costa de Santa Cruz (Patagonia Argentina): alcances y resultados. Magallania 31: 69-94. Ceci, L. 1984 Shell midden deposits as coastal resources. World Archaeology 16 (1): 62-74. Claassen, C. 1998 Shells. Cambridge Manuals in Archaeology. Cambridge Press, Cambridge. 2000 Quantifying shell: comments on Mason, Peterson and Tiffany. American Antiquity 65 (2): 415-418. Dupont, C. 2003 La malacofaune de sites mésolithiques et néolithiques de la façade atlantique de la France: Contribution à l’économie et à l’identitéculturelle des groupesconcernés, BAR International Series 157. Archaeopress, Oxford. Farinati, E. and C. Zavala 1995 Análisis tafonómico de moluscos y análisis de facies en la serie holocena del río Quequén Salado, provincia de Buenos Aires, Argentina. In Actas del Sexto Congreso Argentino de Paleontología y Bioestratigrafía, pp. 117-122. Trelew, Argentina. Favier Duvois, C. and F. Borrella 2007 Consideraciones acerca de los procesos de formación de concheros en la costa norte del Golfo San Matías (Río Negro, Argentina). Cazadores Recolectores del Cono Sur 7: 152-165. Favier Dubois, C. and M. Bonomo 2008 Geoarqueología en la Localidad Nutria Mansa (Pdos. De Gral. Alvarado y Lobería, Provincia de Buenos Aires). Comechingonia 11: 9-28. Fernández López, S. 1999 Tafonomía y fosilización. In Tratado de Paleontología, edited by B. Meléndez, pp. 51-107 and 438-441. Consejo Superior de Investigaciones Científicas (CSIC), Madrid. Ford, P. 1992 Interpreting the grain size distributions of archaeological shell. In Deciphering a shell midden, edited by J. K. Stein, pp. 283-325. Academic Press, New York.

Taphonomic analysis of archaeomalacological assemblages: shell middens on the northern coast of Santa Cruz (Patagonia, Argentina)

33

Glassow, M. A. 2000 Weighing vs. counting shell remains. A comment on Mason, Peterson and Tiffany. American Antiquity 65 (2): 407-414.

Morlan, R. E. 1984 Toward the definition of criteria for the recognition of artificial bone alterations. Quaternary Research 22 (2): 160-171.

Gordillo, S. 2007 Análisis tafonómico de quitones (Polyplacophora: Mollusca) holocenos de Tierra del Fuego, Argentina. Ameghiniana 44 (2): 407-416.

Muckle, J. 1985 Archaeological considerations of bivalve shell taphonomy. Ph. D. Thesis, Department of Archaeology, Simon Fraser University.

Gutiérrez Zugasti, I. 2008 Análisis tafonómico en arqueomalacología: el ejemplo de los concheros de la región cantábrica. Krei 10: 53-74.

Nash, D. T. and M. D. Petraglia 1987 Natural formation processes and the archaeological record: present problems and archaeological analysis. In Natural formation processes and the archaeological record, edited by D. T. Nash and M. D. Petraglia, pp. 186-204. BAR International Series 352, Archaeopress, Oxford.

Hammond, H. and M. A. Zubimendi 2013 Estudio de la composición de sitios concheros en la Costa Norte de Santa Cruz (Patagonia Argentina). In Tendencias teórico metodológicas y casos de estudio en la arqueología de la Patagonia, edited by A. F., Zangrando, R. Barberena, A. Gil, G. Neme, M. Giardina, L. Luna, C. Otaola, S. Paulides, L. Salgán and A. Tívoli, pp. 405-415. Sociedad Argentina de Antropología, Museo de Historia Natural San Rafael e INAPL, San Rafael. Hammond, H., M. A. Zubimendi and L. Zilio 2013 Composición de concheros y uso del espacio: aproximación al paisaje arqueológico costero en Punta Medanosa. Revista del Departamento de Arqueología, Escuela de Antropología, Facultad de Humanidades y Artes 5: 67-84. Kidwell, S. M. 1991 The stratigraphy of shell concentrations. In Taphonomy: releasing the data locked in the fossil record, edited by P. Allison and D. Briggs, pp. 211-290. Plenum Press, New York. Linse, A. R. 1992 Is bone safe in a shell midden? In Deciphering a Shell midden, edited by J. K. Stein, pp. 327-342. Academic Press, New York. Lyman, R. L. 1994 Vertebrate Taphonomy. Cambridge University Press, Cambridge. Mason, R., M. Peterson and J. Tiffany 1998 Weighing vs. counting: measurement reliability and the California school of midden analysis. American Antiquity 63 (2): 303-324. Mason, R., M. Peterson and J. Tiffany 2000 Weighing and counting shell: a response to Glassow and Claassen. American Antiquity 65 (4): 757-761. Moreno Nuño, R. 1994 Análisis arqueomalacológicos en la Península ibérica. Contribución metodológica y biocultural. Ph. D. Thesis, Universidad Autónoma de Madrid, Madrid, España.

Orquera, L. and E. Piana 1999 Arqueología de la región del canal Beagle (Tierra del Fuego, República Argentina). Sociedad Argentina de Antropología, Buenos Aires. 2000 Composición de conchales de la costa del Canal Beagle (Tierra del Fuego, República Argentina), segunda parte. Relaciones de la Sociedad Argentina de Antropología XXVI: 345-368. Pailler, Y., C. Dupont, Y. Sparfel and A. Leroy 2007 Analysef onstionnelle des galets biseautés du Médolithique à la fin du Néolithique dans I`Oquest de la France, la Grande-Bretagne et I´Irlande. Bulletin de la Société Préhistorique Francaise 104 (1): 31-54. Schiffer, M. B. 1983 Toward the identification of formation processes. American Antiquity 48 (4): 675-706. Stein, J. K. 1987 Deposits for archaeologist. Advances in Archaeological Method and Theory 11: 337-395. Villagran, X. S., A. L. Balbo, M. Madella, A. Vila and J. Estévez 2010 Experimental micromorphology in Tierra del Fuego (Argentina): building a reference collection for the study of shell middens in cold climates. Journal of Archaeological Science 38: 588-604. Villamarzo, E. 2009 Estudio experimental sobre valvas de berberechos (Donax hanleyanus). In La arqueología como profesión: los primeros 30 años. XI Congreso Nacional de Arqueología Uruguaya, edited by L. Beovide, C. Erchini and G. Figueiro, pp. 745-754. Asociación Uruguaya de Arqueología, Montevideo. Waselkov, G. A. 1987 Shellfish gathering and shell midden archaeology. Advances in Archaeological Method and Theory 10: 93-210.

34

H. Hammond - Intersecciones en Antropología - Special Issue 1 (2014) 21-34

Waters, M. R. 1992 Principles of Geoarchaeology. University of Arizona Press, Tucson. WoRMS 2012 World Register of Marine Species. Available from http://www.marinespecies.org at VLIZ (accessed 25 June 2012). Zilio, L. and H. Hammond 2013 Distribución de concheros y estructuras de entierro (chenques), en la bahía del Oso Marino (costa norte de Santa Cruz). In Tendencias teórico metodológicas y casos de estudio en la Arqueología de la Patagonia, edited by A. F., Zangrando, R., Barberena, A. Gil, G. Neme, M. Giardina, L. Luna, C. Otaola, S. Paulides, L. Salgán and A. Tívoli, pp. 535-544. Sociedad Argentina de Antropología, Museo de Historia Natural San Rafael e INAPL, San Rafael. Zubimendi, M. A. 2012 Explorando la variabilidad del registro arqueomalacológico en la Costa Norte de Santa Cruz, Patagonia argentina. Intersecciones en Antropología 13: 359-375. Zubimendi, M. A., L. Mazzitelli and P. Ambrústolo 2004 Análisis de la distribución de sitios en la localidad de Punta Guanaco, Costa Norte de Santa Cruz. In

Artefactos líticos, movilidad y funcionalidad de sitios en Sudamérica. Problemas y perspectivas, edited by P. Escola and S. Hocsman. BAR International Series, Archaeopress, Oxford. In press. Zubimendi, M. A., A. S. Castro and E. Moreno 2005 El consumo de moluscos en la Costa Norte de Santa Cruz. Intersecciones en Antropología 6: 121-137. Zubimendi, M. A. and H. Hammond 2009 Análisis de los restos malacológicos en el sitio Los Albatros, Bahía del Oso Marino (Provincia de Santa Cruz). In Arqueología de la Patagonia: una mirada desde el último confín, edited by M. Salemme, F. Santiago, M. Álvarez, E. Piana, M. Vázquez and M. Mansur, pp. 865-878. Utopías, Ushuaia. Zubimendi, M. A., H. Hammond and L. Zilio 2012 Identificación de agentes de alteración del registro arqueológico en la costa norte de Santa Cruz (Patagonia, Argentina): aportes para la conservación del patrimonio. XIX Congreso Nacional de Arqueología Chilena. In CD-ROM. Zuschin, M., M. Stachwitschand R. Stanton 2003 Pattern and processes of shell fragmentation in modern and ancient marine environment. Earth-Science Review 63: 33-82.

|

35

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes María del Pilar Babot, Julia Lund and Adriana Valeria Olmos Received 20 August 2013. Accepted 14 February 2014

ABSTRACT We present comparative material for the identification of culinary residues of cooked tubers of Solanum sp., Oxalis tuberosa and Ullucus tuberosus. We use a broad concept of taphonomy that includes the study of plant modifications resulting from the preparation of food, in this case the boiling and cooking al rescoldo of fresh tubers. We undertake a number of controlled cooking experiments and compare the results with fresh samples. We discuss morphological and optical modifications of tissue fragments and intracellular particles resulting from our cooking experiments. Finally, we discuss the possibility of recognizing cooking techniques from microscopic analysis of tuber remains. Keywords: Taphonomy; Culinary techniques; Plant processing; Starch; Tubers.

RESUMEN TAFONOMÍA EN LA COCINA: PRÁCTICAS CULINARIAS Y RESIDUOS DEL PROCESAMIENTO DE PLANTAS TUBEROSAS NATIVAS DE LOS ANDES CENTRO-SUR. Presentamos material comparativo para la identificación de residuos culinarios de tubérculos cocidos de Solanum sp., Oxalis tuberosa y Ullucus tuberosus. Partimos de un concepto amplio de tafonomía que incluye el estudio de las modificaciones de las plantas resultantes de la preparación de alimentos; en este caso, aquellas que se deben al hervido y cocción al rescoldo de tubérculos frescos. Realizamos experimentos de cocción controlados y comparamos los resultados con muestras frescas. Describimos las modificaciones en los atributos morfológicos y ópticos de tejidos y partículas intracelulares resultantes de nuestros experimentos de cocción. Finalmente, discutimos la posibilidad de reconocer las técnicas de cocción a partir del análisis microscópico de vestigios de tubérculos. Palabras clave: Tafonomía; Técnicas culinarias; Procesamiento de plantas; Almidón; Tubérculos.  

María del Pilar Babot. Instituto de Arqueología y Museo, Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán (IAM, FCN e IML, UNT). Instituto Superior de Estudios Sociales - Consejo Nacional de Investigaciones Científicas y Técnicas-UNT (ISES-CONICET-UNT). San Lorenzo 429 (4000), San Miguel de Tucumán, Tucumán, Argentina. E-mail: [email protected] Julia Lund. Instituto de Arqueología y Museo, Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán (IAM, FCN e IML, UNT). San Martín 1545 (4000), San Miguel de Tucumán, Tucumán, Argentina. E-mail: [email protected] Adriana Valeria Olmos. Instituto de Arqueología y Museo, Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán (IAM, FCN e IML, UNT). San Martín 1545 (4000), San Miguel de Tucumán, Tucumán, Argentina. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 35-53. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

36

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

A TAPHONOMIC APPROACH OF CULINARY TRANSFORMATIONS   This work is part of a series of studies initiated over a decade ago (Babot and Korstanje 2001; Babot 2003), aimed at generating comparative material for identifying plant processing techniques from microscopic analysis of preserved residues of plants native to the south-central Andes. It is worth noting that the transformations and agents involved in such preparations (e.g., cooking) go beyond the scope of food, as medicinal or ritual uses can also be important. Thus, although the perspective of this work is culinary, this is only circumstantial; the emphasis is on how techniques, as modes of transformation, affect matter (Pazzarelli 2012). This study deals with the cooking of tuberous plants of the genus Solanum L. (Solanaceae), “potatoes”; Oxalis tuberosa Mol. (Oxalidaceae), “oca” and Ullucus tuberosus Caldas (Basellaceae), “ulluco” or “papa lisa”. We began with an ethnobotanical approach that considers the traditional uses of plants in the southcentral Andean region and the various means by which tubers become food. We developed experiments to obtain tubers cooked al rescoldo and boiled tubers, which may themselves constitute simple foods, based on a single ingredient, or be part of complex preparations with other plant, animal and mineral ingredients. We rely on a broad concept of “recipe” “[...] as a more or less flexible or open formula to achieve a preparation” (Babot et al. 2012: 242). The components of a recipe are its ingredients in relative amounts and combinations, the modes and techniques of preparation and service, the circumstances of its use, the implements required throughout the process, and the spatio-temporal context and the actors involved in the culinary performance (Babot et al. 2012). Of all these components, this paper deals with tubers as ingredients in recipes, and with methods of tuber preparation. Preparation sequences are not rigid or linear because a food element can be associated with multiple recipe pathways of different length and complexity (Babot 2009). “So, when we refer to old recipes, we refer to approximations to the modes of preparing foods, rather than to strict and closed models of the ingredients, their preparation and presentation [...]” (Babot et al. 2012: 241). The taphonomic study of food residues gives us a unique perspective on how plants, animals and minerals were transformed into food and their subsequent history to the point of archaeological recovery and analysis. According to the “unrestricted taphonomy” approach (Borrero 2011) we use a broad definition of the concept as the study of the decomposition “or modification” of organisms, their parts or products, and of the processes leading to their accumulation and

differential preservation in archaeological contexts, so that they can be genuine sources of archaeological information (Lewarch and O’Brien 1981; Borrazzo 2006). We are particularly interested in assessing how such a perspective can inform our interpretation of past human practices. Thus, we consider the modifications of plants’ useful parts associated with different methods of food preparation, which condition the appearance and integrity of such food remains as recovered from archaeological contexts. Such modifications can be explained in terms of different physico-chemical processes that affect the structure and the properties of starch and other vegetable intracellular particles, and histological elements (Babot 2003). Previous work has demonstrated the utility of taphonomic and experimental approaches to the macroscopic and microscopic analyses of the modes and procedures for preparing animal or vegetable foods (e.g., González and Frère 2004; Gong et al. 2011; López et al. 2011; Lovis et al. 2011; Raviele 2011; Babot et al. 2012 and references therein; Lantos et al. 2012). In particular, our approach focuses on the micro-morphological characterization of such modifications. In this study, we characterized the anthropic/ culinary modifications of micro-particles and tissue fragments in different varieties of tubers of three genera, which allowed us to formulate expectations for archaeological cases. Thus, the various stages of investigation aimed to: 1) characterize fresh tissues of different varieties of potato, oca and ulluco, since these are ingredients in traditional culinary preparations and recipes; 2) observe how aspects of the fresh tissue of potato, oca and ulluco change or disappear as a consequence of two traditional food preparation methods (boiling and cooking al rescoldo until completely cooked), and identify which new elements appear in processed foods, explaining these on the basis of the physico-chemical processes involved; and 3) compare the two sets of observations to identify taphonomic signatures of these culinary practices in archaeological situations.

THE TAPHONOMY OF MICROFOSSILS Current Perspectives The taphonomic study of plant microfossils and their archaeological associations is a versatile approach. Some taphonomic researches focus on the ways various biological (e.g., soil fauna and roots) and environmental agents (e.g., pH, moisture and temperature conditions, salt precipitation and transport) alter the microfossil record and affect its survival and integrity (Therin 1994; Hart 2003; Humphreys et al. 2003; Haslam 2004; Barton and Matthews 2006; Osterrieth et al. 2013; Musaubach and Babot 2014, among others).

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes These studies also consider humans, through the manipulation of the natural environment, as an agent of transformation, since they can modify plants and their microfossil remains through residential use of certain places, agriculture, or burning (Therin 1994; Parr et al. 2008; Osterrieth et al. 2009, among others). These kind of taphonomic researches have focused on analysis of biosiliceous particles, calcium phytoliths and starch from the perspective of paleoecological, pedological and archaeological problems. Previous work has also included study of the effects of different laboratory manipulations on the integrity and composition of microfossil assemblages that are ultimately observed under the microscope. Many of these recent studies also involved revision of sample extraction and treatment protocols with particular attention to archaeological applications (Babot and Korstanje 2001; Coil et al. 2003; Korstanje 2003; Babot 2007; Korstanje and Babot 2007; Torrence and Barton 2007, etc.). Other taphonomic studies closely related to the analysis of use residues on archaeological artifacts assess the survival rates and prospects of starch -one of the main microfossils useful for these purposes- under different conditions of entrapment, depth, sediment compaction and exposure, and considering the passage of time according to the nature of the processed substance (Lu 2003; Babot and Bru de Labanda 2005; Barton and Matthews 2006; Langejans 2010, among others). The potential for post-depositional contamination has also been discussed (Barton et al. 1998). Related to taphonomic studies but following different approaches are archaeologically or bromatologically inclined histological studies designed to understand the feasibility and reliability of identifying plant tissues exhibiting different degrees of fragmentation and preservation (Pochettino and Scattolin 1991; Cortella and Pochettino 1994). We are optimistic about the possibility of obtaining archaeological information from taphonomic and contextual approaches and we consider residues (meaning remains in general, rather than a priori use residues) as dynamic systems that can provide data about use, the contemporaneous context for such use, processes subsequent to deposition, and the manufacture of associated artifacts (the latter when microfossils are included in the artifact raw materials) (Babot and Haros 2008; Hart 2011; Babot et al. 2012). Thus, when considering plant residues located on an artifact or in an archaeological matrix, it would hypothetically be possible to identify interfaces. In the first case, such interfaces would be artifact/residue/ sediment matrix after deposition, where the microfossil “signal” attributable to the raw materials would decrease from the artifact mass to its surface; the “signal” related to use would decrease from the surface of the artifact to the sediment matrix, and the “signal” of the matrix

37

would follow an opposite tendency to that of use. Hence, precautions taken during sample extraction and the criteria used to interpret manufacture, use and context are very important (Babot and Haros 2008; Zucol and Loponte 2008; Hart 2011). The exchanges, gains, losses and modifications of material that occur at the interfaces between object, use residue and matrix must be considered, including other processes that may occur between the time archaeological remains are extracted and analytical data are obtained. Sometimes, burial conditions can promote the preservation of residues, degradation byproducts and new products resulting from interactions with the sedimentary matrix (Jones 2009). This applies to different types of elements contained in the residues, whether chemical, histological or intracellular. In this regard, we consider that interpreting the nature of a residue requires knowing the particular history of the object under analysis. In other words, a residue could indicate 1) the last recorded use of an artifact (Haslam 2006), or 2) successive use episodes recorded in the stratification of the remains (Musaubach and Beron 2012), or 3) random averaging (in a broad sense rather than referring to statistical significance) resulting from repeated use, partial cleaning between successive uses, differential decay of components and exchanges between the environment, the object’s mass and the residue, plus laboratory treatments (Babot 2007; Babot et al. 2012).   A taphonomic approach to plant microfossils and anthropogenic manipulations A small number of studies have discussed the transformation of tissues and intracellular particles resulting from anthropogenic manipulation of plants. Examples include the identification of striae on the surface of silica phytoliths obtained during threshing of silica-rich taxa (e.g., European grains); the transformation of calcium oxalate crystals into calcite pseudomorphs, which occurs during combustion (Juan-Tresserras 1992); the fracture of biosiliceous particles as a result of activities such as grinding (Checa et al. 1999); and the tearing and disarrangement of plant fibers during mastication (Musaubach and Babot 2014). The formation of new products during cooking (e.g., micro-charcoals and particle clumps) has also been documented (Babot 2003; Tassara and Osterrieth 2008, among others). Starch is one of the most studied intracellular particles, both in archaeology and other fields. Analyses of the physico-chemical processes that can alter starch have a long history, linked initially to biological and food industry interests (e.g., Radley 1943; Whistler et al. 1984). These studies have addressed aspects including starch grains’ loss of structure and birefringence properties through contact

38

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

with caustic chemicals, heat in the presence of water, the action of enzymes during seed germination, and the sprouting of underground organs. The first applications of this knowledge to archaeological situations were related to questions about food, particularly brewing, grinding and boiling of starchy plants (e.g., JuanTresserras 1992; Loy 1994; Checa et al. 1999). These studies, along with the work of Babot (2003), Beck and Torrence (2006), Fullagar (2006), Samuel (2006), Henry et al. (2009), Gong et al. (2011) and Crowther (2012), are directly related to our research, as they consider the effects past anthropogenic manipulation of plants had on their starches. Babot’s (2003) research aimed to develop modern comparative standards for application to archaeological cases (Babot 2009; Babot et al. 2012, etc.), and has focused on the optical and morphological effects of various processing techniques on starch (e.g., aeration, sun drying, toasting, ashing, freezing, desaponification/washing -i.e., removal of saponins-, and grinding). Babot’s research also includes recognition of various cooking practices from starchy residues. Beck and Torrence (2006) considered the paths of starch when used for different purposes in various cultural contexts. Fullagar (2006) evaluated the role of experiments in the functional assessment of archaeological artifacts, and Samuel (2006) discussed various ways in which modified starch has been preserved, including bread and yeast residues. Henry et al. (2009) documented the progression of starch damage due to the baking, boiling, drying, and fermentation of domesticated legumes and grass seeds, and found boiling to be the most harmful cooking technique for starch. Gong et al. (2011) studied food remains from exceptionally well preserved mortuary offerings, and developed experiments to aid identification of culinary preparations. Crowther (2012) discussed the influence of moisture on starch during cooking. These studies of cultural manipulations have shown that, although they are modified, starch and other intracellular elements can survive multiple food preparation processes. Drying, heating, the breaking down of tissues by trampling and friction, and the formation of ice crystals, all generate physico-chemical changes in those particles, modify their completeness and degree of crystallinity, and produce optical and morphological changes in some grains (Babot 2003). While the damage caused by different food processing techniques may look similar, and although sometimes the same process can alter the starch from different biological sources in different ways (Babot 2003; Henry et al. 2009), it has been shown that, in general, distinct damage patterns seem to result from different processes (Babot 2003). Also, it has been documented that the more intense the process, the greater the severity of the damage. In addition, it is sometimes possible to infer the consecutive stages of processing, which are present as damage patterns superimposed

on the same individual starch granule or on different granules within a sample. Damaged starch grains are more susceptible to hydrolytic agents and fungal and bacterial activity than well-preserved starch. This is attributed to infiltration of the grains’ interior via cracks associated with the damage (Radley 1943; Cortella and Pochettino 1994) and to structural weaknesses resulting from physicochemical changes to the granules. However, research on ancient starch has shown that it is possible to recover damaged grains from both modern and archaeological contexts, as this carbohydrate’s pseudocrystalline structure survives the passage of time even when damaged. Ancient starch analyses with a taphonomic perspective have increasingly focused on damaged starch grains (alongside those recovered intact), as well as the natural and cultural causes of the observed changes. In addition, appropriate and specific terminologies for the description of alteration processes and damage have been adopted (Babot 2003; The International Code for Starch Nomenclature [ICSN 2011]), referring to the so-called modified starch (sensu Samuel 2006; ICSN 2011). This category and one referred to as resistant starch1 have been distinguished from native starch, which refers to unaltered grains. Such studies have recognized certain traits that have a taphonomic rather than taxonomic origin, and have proposed that damaged starch is a source of information regarding cultural practices and postdepositional processes. Damage patterns have also been used to evaluate contamination by assessing the coherence between the types of damage and the archaeological context from which the starch was recovered (Babot 2003). Previous publications have proposed descriptors for modified starches, but when studying human practices we suggest it is possible to rank those descriptors by grouping them following hierarchical categories: a) techniques: modes of transformation implemented by humans; b) agents other than humans -the latter included in a- ; c) physico-chemical processes triggered by human activities and their results or the final state of the mass of material processed, and, finally, d) morphological and optical damage and modifications or changes that are verified in starch grains within the mass (Table 1). Following Lyman’s (1994) terminology, applied techniques and resulting physico-chemical processes constitute taphonomic processes, where the taphonomic agents are the physical, chemical and biological factors involved in the transformation of grains. In this case humans are the default participants in technical manipulation. Finally, the taphonomic effects are the results of these processes and the specific patterns of damage and changes that may be identified histologically and

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes described in morphological and optical terms (Table 1). Thus, for example, what we observe as a paste or a mixture of cooked food that includes resistant and modified starch “damaged in various ways” is a modification due to the retrogradation that occurs when boiled dough is left to rest, or a modification due to the melting by heating in a medium with low water content (Radley 1943; Johnson et al. 1990). The two main physico-chemical processes we address in this paper, gelatinization and melting, are described in previous works. The effects of heating in a wet medium have been studied extensively, especially for the generation of baseline information on the properties of starch for industrial purposes. It leads to a non-reversible process called gelatinization (Radley 1943). 

39

PROCEDURES AND MATERIALS Tuber samples were obtained from traditional vending stalls in Jujuy Province (Argentina) in 2010 and 2012 and Villazón (Bolivia) ​​in 2012. We obtained 19 ethnovarieties of potato (Solanum L.), 4 of oca (Oxalis tuberosa Mol.) and 3 of ulluco (Ullucus tuberosus Caldas), all from rural areas. Here we selected 10 varieties of potato, 2 of oca and 1 of ulluco, which were sampled and processed for culinary purposes. The purpose of using different ethno-varieties was to assess whether there were variations if different kinds of potatoes were subjected to different processing techniques, particularly since they could have been used in different traditional culinary practices (Castro 2008).

In all ethno-varieties, cortex and periderm were sampled separately from the vascular parenchyma and medullary tissue. Cortex and periderm were separated under the assumption that they were part of the “shell” that was eventually removed or peeled prior to consumption, while the parenchyma and the medullary tissue constitute the soft part intended for consumption. Three types of samplings were used for the fresh tubers to obtain reference material: 1) soft scrapings and histological cuts done freehand with a scalpel to obtain thin sections (Babot 2007), 2) diaphanization (a technique in which the Techniques Physico-chemical tissue is treated with an Morphological and optical modifications Processes and Agents (Modes of Taphonomic effects oxidizing agent to make Results transformation) it transparent whilst Loss of defined shape and structure Liquid water Gelatinization Heating in humid manifested in the swelling, bursting, hilum (Radley 1943). + medium (chemical) retaining fabric), and 3) opening and projection of grains, loss of Irreversible – temperature dry ashing (Piperno 1988). birefringence (Babot 2003), and the presence Gelatinized material (heat) e.g.: boiling of exudates (Messner and Schindler 2010), Some washing of the ash collapsed (Williams and Bowler 1982) or material was incorporated emptied grains (ghosts) (Radley 1943) Formation of pastes (Biliaderis 2009), in Retrogradation Rest of the boiled mass Chemical as well to assess tissue which damage and modifications related to forces (Jacobson et al. after cooking loss by this procedure. 1997) – Retrograded gelatinization can be observed (chemical) material or paste e.g.: airing or standing The first two sampling Loss of the structure manifested in the Temperature Melting (Biliaderis Heating in medium techniques provided 2009). Irreversible – formation of pastes (Biliaderis 2009), (heat) + with low moisture references regarding tissue Melt or paste projection and/or opening of the hilum in liquid water content (chemical) grains, loss of birefringence (Babot 2003) (residual e.g.: toasting or appearance and various moisture) roasting elements of tissues, such Swelling (Williams and Bowler 1982) or Hydration, dehydration Liquid water Hydration, shrinkage (Radley 1943) of the grains, dehydration (Radley (or relative in cold (chemical) as ergastic substances increase or decrease of the relief (e.g., flat 1943). Reversible – humidity) + (starch, cellulose and Hydrated or temperature relief) and of the birefringence and the e.g.: soaking, sun visibility of lamellae (Babot 2003) dehydrated material (cold) crystalline calcium salts), drying, airing Grains in different states of disaggregation or Breakage Disaggregation Abrasion, percussion of interest to archeology disarrangement, with presence of physical mechanical (Babot 2003), (mechanical) because they survive discontinuities such as fracture, truncation, forces mechanical cracking; surface damage such as depressions breakage. as microfossils. These e.g.: milling, mashing or dents (Babot 2003) and collapse (Williams Irreversible – and pounding procedures allowed us and Bowler 1982) Disaggregated material to observe intact tissue Presence of physical discontinuities of the Dehydration, Solid water Freezing (mechanical) and fragments in different grains such as breakage and cracking, mechanical + e.g.: making chuño, a stages of disintegration, fragmentation (Babot 2003), collapse breakage. temperature dehydrated form of (Williams and Bowler 1982), emptying Irreversible – (cold to the potato obtained by as well as free cells and Dehydrated material (ghosts) (Radley 1943), decreased relief (e.g., point of freeze-drying (Pardo intracellular elements. freezing) flat relief) and brightness (Babot 2003) and Pizarro 2008) Controlled diaphanization Amylolytic Amylolysis. Loss of structure manifested in the presence of Enzymatic attack (bioenzymes Irreversible pitting (French 1984; Juan-Tresserras 1992), chemical) at temperatures below deep grooves and corrosion (Reichert 1913) e.g.: malting 10°C thinned the material Table 1. Techniques, agents, physico-chemical processes and results, and morphological for better observation.

For dry heating or for heating with low moisture content, we consider the “dry-cooking series”, toasting/ cooking al rescoldo/cooking on embers/roasting/ charring2, wherein the relative intensity of the heat and, therefore, the thermal alteration of the granules, increase from toasting to charring (Radley 1943; Babot 2003). Direct contact with the heat source differentiates roasting, charring and cooking al rescoldo from toasting and cooking on embers, with heat contact being indirect in the latter.

and optical modifications relevant to the study of human manipulation of starchy substances.

40

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

Dry ashing allowed for recovery of the silicified tuber tissues. Due to the low proportion of silica produced by these plants, after the first trials, we avoided to wash ash samples because doing so results in a significant loss of material. Cooking experiments included: a) boiling until cooking was complete, transforming the starch-rich parenchyma and medullary tissue by heating it to boiling in a humid medium with sufficient water; b) cooking al rescoldo (in direct contact with embers and ashes) until cooking was complete, transforming tissues by heating them at moderate temperature in a dry medium or in the presence of tuber residual moisture. Cooking enables consumption, increases energetic value of tubers and eliminates the causes of indigestion (Wandsnider 1997). Boiling was performed using a stove; tubers were placed in a metal container filled with potable water to avoid contamination. Unpeeled tubers were boiled separately, reaching an average of 99ºC during the time needed to soften the parenchyma and medullary tissue (between 15-20 minutes). Tubers started to loss their peel and stain water before completely cooked. Pink oca stained the water and started to loss their peel after 15 minutes in the boiling water. Nine minutes later it was completely cooked. White oca lost their peel at 17 minutes and started to smell like boiled sweet potato. Eight minutes later it was completely cooked. Ulluco took 19 minutes to begin staining the water, losing a minimal amount of peel. Two minutes later was completely cooked. Potatoes took 24 minutes to cook completely. Cooking al rescoldo was done in a backyard fire. The fire was started with quebracho blanco (Aspidosperma quebracho-blanco Schltr.) wood. Red hot embers were produced and gradually covered with ash, at which point the charcoal was not as hot as in its red-hot state. A layer of embers and ashes was dispersed on the firebrick floor. Whole, unpeeled tubers were set over the embers and ashes and exposed to the heat source until the parenchyma and medullary tissue were softened, simulating the effect of placing tubers on the periphery of an active fire. This is a dry-cooking technique different from others such as toasting, cooking on the flame or on embers with a grate, or in ovens. Cooking on the flame involves direct contact of food with the heat source; placing a grate between the food and flame or red-hot embers separates food from the heat source. Toasting requires an intermediate object (e.g., a stone or vessel) to avoid direct contact with fire and buffer heat (Pazzarelli 2012). Cooking al rescoldo is a moderatetemperature procedure traditional in northwestern Argentina, where food is put into embers and ashes, coming into direct contact with the heat source. In our experiment, cooking al rescoldo took between 1015 minutes depending on the type and size/form of

the tuber and degree of exposure to the heat source. Ocas cooked most quickly, followed by ullucos and longer/thinner potatoes and, finally, thicker potatoes. During this process the tubers were not covered, so the periderm was carbonized where directly in contact with embers. Differences in the humidity of the cooked mass were observed in areas near carbonized and noncarbonized periderm. Oxygen and temperature might have fluctuated between the periphery and the center of the ember and ash layer within the range of 100200ºC. Quebracho blanco provided a strong, slow, constant and non-sparking charcoal combustion, with low ash production. Boiled tubers and those cooked al rescoldo were wrapped in aluminum foil and refrigerated until sampling was complete. Sampling followed the same procedures used for fresh specimens (see above). Fresh, dry-ashed and cooked specimens were mounted on slides for viewing and photographing using a polarizing microscope (200X to 630X). Assemblage analysis focused on the various histological elements and intracellular particles present. Characteristics recorded for fresh samples include: cell shape in two- and three-dimensions, arrangement of tissue cells (tiled, linear, concentric, etc.), color with and without polarizer, birefringence, cell size, presence of conduction elements and their characteristics, presence of cellulose in the cell walls; presence, kind, shape, color, presentation and location of calcium salt bodies within the tissues (isolated, grouped); and the occurrence of starch in the reserve parenchyma and the medullary tissue, and its disposition (isolated, in clusters, massively filling the tissue). The same characteristics were observed in food samples, with special attention to the features preserved, modified, and originated from culinary practices. In the case of native and modified starches, the specific variables summarized in the ICSN (2011) and previous studies were recorded (Korstanje and Babot 2007 and references therein; Henry et al. 2009). As mentioned, rather than a detailed description of individual starch grains, the presence of various attributes was confirmed (Table 1). Observations proceeded from questions such as: What is the general state of preservation of the intracellular particles and tissues in our samples? What is the degree of alteration? How does alteration vary with cooking techniques and their relative “aggressiveness”? Have the integrity, visibility, shape, size, color, spatial arrangement, optical properties or textures of tissues, cells and ergastic substances been altered? If so, how? Have any elements or distinctive features of fresh tissues disappeared? Have any new elements arisen as a result of processing? Finally, we compared the two sets of observations, which allowed us to generate expectations for documenting foods made ​​from potatoes, oca and ulluco based on archaeological residues (Tables 2 and 3).

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes Characteristic microscopic features on periderm and cortex from tubers Specimens cooked al rescoldo Boiled specimens

Crystals

Silica deposits

CE

Aspect of tissue

Fresh specimens

New products

41

Preservation of original tissue structure by sections. Tissue fragmentation and intense cracks in the form of tears and joined cell fragments; presence of folds in tissue fragments. Distension, loss of turgor of the tissue with increased apparent size. Thinning of the tissue and loss of relief

General preservation of the original fabric of the tissue. Deformation and fragmentation by sections, with presence of net cracks and folds. Thermal alteration varies between complete carbonization and mild impact by heat. Dehydration and shrinkage; loss of relief and aging. Greatly affected tissues become brittle and in particles Opaque tissue, slightly translucent or transparent according to the effect of heat Staining of the tissue in brown-reddish tones until reaching black in carbonized sections. Loss of the original color. In oca, all tissues appear birefringent under polarized light The birefringence of cellulose is preserved or emphasized

Transparent and diaphanous tissue

Sections of the tissue with intracellular deposits of amorphous silica (polyhedral or globular cells and vessel elements) stand out due to their higher profile

Colorless silicified tissues (silica phytoliths) with gray-black hues detached as a result of the thermal alteration. If not detached, they stand out from the surroundings due to their higher relief

Colorless silicified tissues (silica phytoliths) with gray hues detached as a result of the thermal alteration. If not detached, they stand out from the surroundings due to their higher relief

Polyhedral, tabular druses, crystal sand and subrounded discoid or globular particles. Scattered in the tissue or grouped in the intracellular space -

Crystals very clearly observed in situ or detached from the tissue. They look unaltered; their birefringence is retained or accentuated. Eventual partial melting of the crystalline surface

Crystals very clearly observed in situ or detached from the tissue, located close to the cell walls or completely expelled from the tissue. They may look unaltered. Evidence of partial melting. New clumps of melted crystals are formed -

Turgid tissue, transparent, with mosaic-like fabric, tight or dense with straight-sided polyhedral cells, occasionally rounded

Transparent tissue Non-birefringent and colorless tissue, or heterogeneously colored, depending on variety Thickened cell walls with thick birefringent cellulose enrichments

-

Clumps of organic matter isolated or attached to the tissue, with a matrix of unctuous appearance colored in brown-reddish tones, in which crystals and occluded micro-charcoal stand out (verified in extensive sections, or in particles) Massive carbonization by sections (outer areas of the tubers) and presence of micro-charcoal abundantly distributed throughout the tissue

It can vary between color preservation, partial loss of color in parts of the tissue, or preservation of parts with watery or diluted coloration (brown-reddish tones). In oca, all the tissues appear birefringent The birefringence of cellulose is preserved or emphasized

Micro-charcoals or carbonized tissues were not observed

Table 2. Characteristic features of the periderm and cortex of fresh and boiled tubers, and tubers cooked al rescoldo. Note: CE= Cellulose. Specimens cooked al rescoldo

Turgid tissue, transparent and dense with polyhedral and globular cells with thin walls

Tissues remain structured; cells remain close but not attached to each other, or completely detached and with a globular appearance. Dented and rough surface of cells, contracted, cracked, with lower relief. Although dehydrated, some degree of turgor persist; some cells are partially or fully collapsed

Tissues remain structured; cells remain close but not mutually attached, or are disaggregated and dispersed with a globular appearance. Distension, loss of turgor or firmness. Cells with cracks and fractures, partially or totally collapsed, depending on the preservation of their content

Colorless to slightly browngrayish tissue

Colorless to slightly brown-grayish tissue is maintained.

Cells with thin cellulose walls

The cellulose thickenings are preserved, and their birefringence stands out in some cases. This element highlights the fabric of the tissues

Colorless to slightly brown-grayish tissue is maintained. Tissues became diaphanous. A staining of the tissue may occur in watery or diluted brown-reddish hues The cellulose thickenings are preserved, and their birefringence stands out in some cases. This element highlights the fabric of the tissues

Closely packed cells, filled with birefringent starch grains

The starch content is completely absent, giving the tissue an empty appearance, or the starch content is in different stages of the meltinggelatinization process. The birefringence varies depending on the situation. There are exudates of amorphous starch within and outside of the tissues Amorphous starch masses dominate in the interior of the tissue. Occasional clumps or isolated individuals of modified starch with damage due to heating (open hilum, darkened sections, peripheral cracks and damage to the extinction cross and the birefringence). Little to no presence of unaltered resistant starch Crystals preserve their location in the tissue. Expulsion events of crystal clusters and microcrystals into the intercellular space They are preserved unaltered within or outside the tissue

VE

CR

Starch

CE

Aspect of tissue

Characteristic microscopic features on parenchyma and medullary tissue from tubers Fresh specimens

Supernumerary simple starch grains

Calcium crystals dispersed in the tissue Dense clusters of vessel elements, birefringent, silicified or not

Boiled specimens

The starch content is completely absent, giving the tissue an empty appearance, or the starch content is in different stages of the melting-gelatinization process. The birefringence varies depending on the situation. There are exudates of amorphous starch within and outside of the tissues Amorphous starch masses dominate in the interior of the tissue. There is unaltered resistant starch as isolated and scarce grains, and grains of modified starch in individual gelatinization process of (open hilum, damage to the extinction cross and birefringence, longitudinal cracks) forming clumps associated with starch exudates Crystals preserve their location in the tissue. Expulsion events of crystal clusters and microcrystals into the intercellular space They are preserved unaltered within or outside the tissue

Table 3. Characteristic features of the parenchyma and the medullary tissue of fresh and boiled tubers, and tubers cooked al rescoldo. Note: CE = Cellulose; CR = Crystals; VR = Vessel elements; NP = New products.

42

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53  RESULTS

Description of fresh tuber specimens Periderm and cortex tissues are turgid and present a tight or dense mosaic-like fabric of polyhedral cells (Figure 1; Table 2). The tissue is non-birefringent -with the exception of periderm cell walls that are cellulose enriched- and either colorless or colored by sections (Figure 1a-b). The presence of calcium salt crystals (primarily calcium oxalate) is variable (Figure 1). They occur as polyhedra in oca and ulluco (Figures1 i-n, p-r); tabular druses and crystal sand in oca, ulluco and Solanum (Figure 3o-p); and flat, rounded or globular particles in Solanum (Figure 1h). Parenchymal and fresh medullary tissue cells are polyhedral and globular, with thin and less celluloseenriched membranes than the periderm. They are closely packed and contain numerous starch grains of the type described previously (e.g., Korstanje and Babot 2007 and references therein), completely filling reserve tissue (Figure 5u, Table 3). Abundant calcium crystals are observed in ulluco and oca parenchyma (Figure 7i-n); in Solanum, crystal abundance depends on the variety (Figures 4c, e and 5ef). Dense clusters of birefringent conducting elements are observed, especially in the section corresponding to the vascular ring (Figures 5a-b and 7f-g).

Description of tuber specimens cooked al rescoldo Carbonized or highly thermally altered sections of the periderm and cortex appear opaque to slightly translucent under the microscope. The internal structures and content of some tissues are difficult to observe, but in other sections, birefringent elements stand out well (Figures 2d-f, o-r and 3k-m; Table 2). Parts of the

Figure 1. Appearance of the fresh periderm and cortex of: a-h) Solanum, i-n) Oxalis tuberosa and o-r) Ullucus tuberosus. a-b) Pentaoca, c-d) Abajeña, e-f) Huanco Suyo, g-h) Solanum 1a, i-l) Pink oca, m-n) White oca, o-r) Ulluco. The contiguous twin micrographs correspond to views with parallel (left) and crossed (right) nicols of the same tissue.

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes

43

3n, p). In a few cases, partial melting of the druses’ tissues that were not in direct contact with fire are crystallites is observed (Figure 3i). less thermally altered (Figure 2a-c, h-I). Silicified parts stand out from the tissues around them due to a higher Parenchyma and medullary tissues may retain their relief than the periphery. Occasionally, they appear original structure. In other cases, cells remain close as isolated polyhedral or globular siliceous particles without completely attaching to each other, or are (Figure 3k, g-h). Some deformation, fragmentation, entirely detached. Their surfaces are dented, rough, crack and folds are observed, but this kind of damage is contracted, cracked, and have lower relief than fresh less pronounced among tubers cooked al rescoldo than internal tissues (Figures 4-5; Table 3). Despite being among those that were boiled (Figures 2c-d, p). Tissues significantly affected by heat become brittle, dehydrated and shrunken. They are stained reddish-brown to black (in carbonized areas), which accentuates surface irregularities regardless of the original periderm color. Microcharcoals are abundant throughout the tissue; some of them are still recognizable in the inner layers (Figures 2a-c, h-i, k-n, g and 3d-f, j, q). Typically, it is possible to observe isolated clumps, or clumps attached to the tissue, within an unctuous, reddishbrown matrix, against which crystals and occluded microcharcoals stand out. This pattern occurs in both extensive and restricted sections of tissue (Figures 2g-h, k-n and 3d-f, g-h, q). Cell wall cellulose birefringence is retained or increased. In the cells of oca, birefringence is widespread, not restricted to cellulose accumulation (Figure 3n, r). Conducting tissues remain unaltered. Calcium crystals also remain largely unaltered, although t h e i r Figure 2. Appearance of the periderm and cortex cooked al rescoldo of: a-o) Solanum sp. and birefringence stands p-r) Ullucus tuberosus. a-c) Desireé, d-i) Abajeña, j-n) Malcacha, o) Huaico potato, p-r) Ulluco. The contiguous twin micrographs correspond to views with parallel (left) and crossed (right) nicols out (Figures 2r and of the same sample.

44

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53 retained. Although the crystals can maintain their location within the tissues (Figure 4c, e), clusters of multiple crystallites are often found in the intercellular spaces due to their expulsion from the interior of the cells (Figure 5e-f). Vessel elements are preserved unaltered, with high birefringence, appearing isolated or in clusters (Figure 5a-b).   Description of boiled tuber specimens

Periderm maintains its configuration and original morphology in some portions, although there is more fragmentation of the tissue than when cooking al rescoldo (Figure 6, Table 2). Highly fragmented, torn or folded sections are observed (Figures 6c, m-r). In general, boiling causes distension, loss of tissue turgor, an increase in size, and loss of relief. Tissues become transparent and noticeably thinner (Figure 6a-f). Colorless to gray silicified tissue and isolated polyhedral Figure 3. Appearance of the periderm and cortex of Oxalis tuberosa cooked al rescoldo. a-j) White cells can be seen. If not Oca, k-s) Pink Oca. The contiguous twin micrographs correspond to views with parallel (left) and detached, they stand crossed (right) nicols of the same sample. out from surroundings tissues due to their higher relief (Figure 6e-f). A watery dehydrated, they retain a degree of turgor, though some or diluted pigmentation remains unaltered or lost by are partially or fully collapsed (Figure 4a). Starches are sections in periderm cells (Figure 6e-f, I, m). Brown in the process of melting/gelatinization (Figures 4e-g, to reddish staining can appear by sections (Figure 6p). j, o-r and 5o-p, s-t) or absent, giving the tissue the Birefringence of thickened cell wall cellulose is retained appearance of being almost totally empty (Figure 4c, (Figure 6j, l, n, r). In pink oca, this phenomenon is i). Clumps (Figure 5s-t) and isolated grains of modified widespread, as with cooking al rescoldo (Figure 6g). starch with damage from dry-cooking are occasionally Calcium crystals may be unaltered and retain their observed (Table 3) (Figure 5g-j, m-n), and unaltered, position in the tissue (Figures 6m, q-r) or be released resistant starch is scarce or virtually absent (Figure into the inter- or extracellular space (Figure 6k, q-r). 5c, k-l). The birefringent cellulose of cell walls is

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes

45

of turgor, and cells appear more distended than when cooked al rescoldo or fresh. In sections more affected by boiling, cells appear collapsed due to the partial or total loss of starch (Figure 7a-e and 8jk). There are cracks and fractures in the cell walls; the surfaces are rough or dented, resembling those of tissues cooked al rescoldo (Figures 7a, e and 8n, r). Increased transparency and areas with watery or diluted reddish-brown staining are observed (Figure 7i and 8b-e). Some nodular particles in the same tones are attached to tissue (Figures 7i-j and 8a, c). Discontinuous masses of gelatinized, amorphous starch are observed in the interior or exterior of the tissues (Figure 8g-h, j-k). Resistant starch occurs as scarce, isolated individual grains (Figures 7c-e, h and 8g-i, l). Modified starch is in the process of gelatinization (Table 3), isolated (Figure 8no, r-s), forming clumps of individuals that have lost their original shape (Figures 7a-b and 8pq), and associated with starch exudates within the tissues or expelled from them (Figure 8j-k). The survival of resistant starch Figure 4. Appearance of parenchyma and medullary tissue of Solanum sp. cooked al rescoldo. a-c) Abajeña, d-g) Desireé, h-i) Malcacha, j-k) Pentaoca, l-r) Huaico potato. The contiguous and of partially gelatinized twin micrographs correspond to views with parallel (left) and crossed (right) nicols of the individuals is greater in the same sample. close proximity of cortex and periderm than in the Occasionally, crystals are found melted, formed into parenchymal and medullary tissue. Vessel elements clumps in which the individuals are not discernable within the vascular parenchyma preserve their (Figure 6j-k). No micro-charcoals or carbonized tissues birefringence and structure forming dense packages are observed in the boiling specimens. with a persistent linear orientation (Figures 7f-g and 8a, c-d, f). In some cases the crystals maintain their  Globular or polyhedral parenchymal and medullary original location within the tissues (Figures 7i-j and tissue cells with rounded edges are present in clusters 8f-h) or are expelled from them to the inter- or extra–although not attached to each other-, or disaggregated cellular spaces (Figures 7k-n and 8m). Some are and dispersed, and there are empty net spaces between partially solubilized (Figure 7n). them (Figures 7-8, Table 3). In general, there is a loss

46

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

Generally speaking, certain reactions are common among tubers cooked al rescoldo and those heated in a moisturerich medium, the latter being a more aggressive transformation technique that compromises the integrity of plant tissues and particles to a corresponding degree. However, damage to the morphology and optical properties of starch caused by cooking al rescoldo is greater than that caused by toasting, as reported elsewhere (Babot 2003). Such damage includes denaturation and a very low specimen count. In the case of cooking al rescoldo, this is influenced by the fact that plant matter is in direct contact with the heat source and subjected to higher temperatures than in toasting. Although both groups of cooking techniques Figure 5. Starch grains, calcium crystals and conduction elements in parenchyma and medullary a n a l y z e d h e r e c a u s e tissue cooked al rescoldo of: a-n) Solanum sp. and o-t) Oxalis tuberosa. Appearance of the s i m i l a r m o d i f i c a t i o n s fresh parenchyma and medullary tissue of Solanum sp. (Huaico potato) is in (u). a-c) Abajeña, and damage, our results d) Huaico potato, e-f) Desireé, g-n) Pentaoca, o-t) White oca. The contiguous twin micrographs indicate that certain correspond to views with parallel (left) and crossed (right) nicols of the same sample. characteristics can be used to differentiate them and also, to distinguish DISCUSSION AND CONCLUSIONS cooked from fresh samples. For them to be applicable in archaeological contexts, we need to evaluate the   Experimental results indicate the potential for survival over time of the characteristics reported here. differentiating two cooking techniques: heating in humid and dry (or low moisture) environments. Based on previous studies, we expected these techniques to be similar in their effects on tubers since both involve the same agents of modification: heat and moisture. In the case of boiling, water is abundant in the cooking environment. By contrast, water is scarce but not totally absent in the “dry-cooking series” techniques. Among the latter, there is an increase in both the temperature gradient and exposure of the matter to temperature. While there are similarities in the effects of the cooking techniques reviewed, the abundance of water clearly leads to gelatinization, while its absence leads, in theory, to melting due to loss of starch humidity, although some degree of gelatinization is also possible.

The periderm and cortex generally survive and retain their original fabric. They react differently to cooking al rescoldo (characterized by reddishbrown staining of tissues; unctuous clumps -isolated, or attached to tissue- with crystals and occluded micro-charcoals; contraction and tissue aging) versus boiling (characterized by diaphanous and thin material, partial preservation of the original watery color, tissue distension). However, the natural color of tuberous plants’ shell could be confused with the effects of cooking on color and mistakenly attributed to anthropogenic modification. In the external tissues, massive carbonization occurs by sections, and the presence of micro-charcoals distributed throughout the tissue occurs only with cooking al rescoldo.

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes

47

contexts, both inside cooking containers where whole tubers were cooked and as discarded peelings (particularly those of bitter tuber varieties). The parenchyma and medullary tissue suffer greater damage than the periderm and cortex. Contraction occurs in cooking al rescoldo, whereas distension is observed with boiling. In the latter case, a diluted reddish-brown staining of the interior tissues may appear, as well as the occurrence of some nodular particles in the same tones. Observed starch alterations are consistent with those reported elsewhere, but a higher intensity of the modifications was verified when cooking al rescoldo, with respect to what was previously documented for toasting (Babot 2003). Despite the poor survival of starch as isolated, identifiable grains, both ins ide or outs ide t he cooked mass, resistant starch specimens are more common in boiled tubers than in those cooked al rescoldo. Both techniques result in modified starch grains. Calcium crystals, conducting tissues and cellulose survive both techniques. Melted or diluted crystals and Figure 6. Appearance of the boiled periderm and cortex of: a-d, g-l) Oxalis tuberosa, e-f) crystals expelled from the Solanum sp. and m-r) Ullucus tuberosus. a-d) White oca, e-f) Pentaoka, g-l) Pink oca, m-r) tissues generally indicate Ulluco. The contiguous twin micrographs correspond to views with parallel (left) and crossed manipulation in a medium (right) nicols of the same tissue. with heat. Nonetheless these changes are more intense in the presence of Results obtained for the most external tissues are water. Wet cooking is also more aggressive to cellulose important for supplementing the data regarding the than cooking al rescoldo. After cooking, cellulose parenchyma and medullary tissue, where the starches allows excellent visualization of the original tissue are primarily located. While the latter are distinctively fabric. Silica deposits, located in conduction and altered by particular processes and, therefore, play an peridermal tissues and usually of little diagnostic value important role in identifying anthropogenic processes, when taken alone, are not affected by the processes under certain circumstances they can be denatured or studied; on the contrary, they tend to stand out from absent, making information about the periderm and the rest of the tissue, either in situ or detached from it. cortex particularly relevant. Additionally, the periderm and cortex tissue can be preserved in archaeological

48

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

Figure 7. Appearance of boiled parenchyma and medullary tissue of: a-h) Solanum sp. (Pentaoca) and i-n) Ullucus tuberosus. The contiguous twin micrographs correspond to views with parallel (left) and crossed (right) nicols of the same tissue.

No significant differences in changes produced by the processing techniques considered here were observed between the three types of tubers and their

varieties. Thus, the expectations generated should apply to a large number of tuberous plants and potentially other resources as well.

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes

49

Figure 8. Appearance of boiled parenchyma and medullary tissue of Oxalis tuberosa. a-q) White Oca, r-s) Pink Oca. The contiguous twin micrographs correspond to views with parallel (left) and crossed (right) nicols of the same tissue.

50

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

Finally, we must acknowledge that the daily character of kitchens and food preparation methods suggests intermediate instances that turn black and white results from controlled experiments into grays which cannot be ignored. For instance, tubers and other items might be cooked in their own liquid, without additional water, which, strictly speaking, is neither boiling nor toasting. Such exceptions and the integrity of the archaeological remains, determine the “grain” of the inferences that can made using experimental data. Despite these caveats, experimental work continues to contribute positively to our understanding of past practices.   Acknowledgments To S. Hocsman, C. Codemo and A. Calisaya for providing the potatoes, ocas and ullucos analyzed in this study. To V. Bajales and J. Vildoza, who participated in sampling of the tubers. To anonymous reviewers for their useful comments on the content and language of this paper. To editors, K. Borrazzo and C. Weitzel for inviting us to publish in this volume and for their help with translation issues. This research was supported by projects CIUNT 26/G404 and PIPCONICET 464 directed by C. Aschero.   REFERENCES Babot, M. P. 2003 Starch grain damage as an indicator of food processing. In Phytolith and starch research in the Australian-Pacific-Asian regions: the state of the art, edited by D. M. Hart and L. A. Wallis, pp. 69-81. Terra Australis 19, The Australian National University, Canberra. 2007 Granos de almidón en contextos arqueológicos: posibilidades y perspectivas a partir de casos del Noroeste argentino. In Paleoetnobotánica del Cono Sur: estudios de casos y propuestas metodológicas, compiled by M. B. Marconetto, M. P. Babot and N. Oliszewski, pp. 95-125. Museo de Antropología, Universidad Nacional de Córdoba, Córdoba. 2009 Procesamiento de tubérculos y raíces por grupos agropastoriles del Noroeste argentino prehispánico: análisis de indicadores en residuos de molienda. In La alimentación en la América precolombina y colonial: una aproximación interdisciplinaria, compiled by A. Capparelli, A. Chevalier and R. Piqué, pp. 67-81. Treballs d’Etnoarqueologia 7, Instituto Milà y Fontanals, Consejo Superior de Investigaciones Científicas (CSIC), Madrid. Babot, M. P. and E. Bru de Labanda 2005 Analysis of three factors that have an influence on the preservation of microfossils in archaeological artifacts. The Phytolitharien 17 (2): 4-5.

Babot, M. P. and M. C. Haros 2008 Interpreting content, context and manufacture from use-residues in ceramic vessels from Southern Argentinean Puna. In Abstracts of the 7th international Meeting on Phytolith Research, edited by M. Osterrieth, M. Fernández Honaine y N. Borrelli, pp. 44-45. Universidad Nacional de Mar del Plata, Mar del Plata. Babot, M. P., S. Hocsman, R. E. Piccón Figueroa and M. C. Haros 2012 Recetarios prehispánicos y tradiciones culinarias. Casos de la Puna argentina. In Las manos en la masa. Arqueologías, antropologías e historias de la alimentación en Suramérica, edited by M. P. Babot, M. Marschoff and F. Pazzarelli, pp. 235-269. Instituto de Arqueología de Córdoba and Instituto Superior de Estudios Sociales, CONICET, Córdoba. Babot, M. P. and M. A. Korstanje 2001 On starch taphonomy: some issues on physical, chemical and possible laboratory damage. In Program of the Conference: The state of the art in phytolith and starch research in the Australian-Pacific-Asian regions, pp. 7-9. Centre for Archaeological Research, Australian National University, Canberra. Barton, H. and P. J. Matthews 2006 Taphonomy. In Ancient starch research, edited by R. Torrence and H. Barton, pp. 75-94. Left Coast Press, Walnut Creek. Barton, H., R. Torrence and R. Fullagar 1998 Clues to stone tool function re-examined: comparing starch grain frequencies on used and unused obsidian artifacts. Journal of Archaeological Science 25: 1231-1238. Beck, W. and R. Torrence 2006 Starch Pathways. In Ancient starch research, edited by R. Torrence and H. Barton, pp. 53-74. Left Coast Press, Walnut Creek. Biliaderis, C. G. 2009 Structural transitions and related physical properties of starch. In Starch: Chemistry and Technology, 3rd ed., edited by J. R. BeMiller and R. L. Whistler, pp. 293-373, Academic Press, Amsterdam. Borrazzo, K. 2006 Tafonomía lítica en dunas: una propuesta para el análisis de los artefactos líticos. Intersecciones en Antropología 7: 247-261. Borrero, L. A. 2011 La función transdisciplinaria de la arqueozoología en el siglo XXI: restos animales y más allá. Antípoda 13: 267-274. Castro, M. V. 2008. La papa (Solanum sp.): contexo social e ideológico en sus zonas de desarrollo originarias. Revista Chagual 6: 33-43.

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes Checa, A., A. Jimeno, J. Juan-Tresserras, J. P. Benito and A. Sanz 1999 Molienda y economía doméstica en Numancia. In Actas del IV Simposio sobre Celtíberos. Economía, pp. 6368. Institución “Fernando el Católico”, CSIC, Zaragoza. Coil, J., M. A. Korstanje, S. Archer and C. A. Hastorf 2003 Laboratory goals and considerations for multiple microfossil extraction in archaeology. Journal of Archaeological Science 30: 991-1008. Cortella, A. R. and M. L. Pochettino 1994 Starch grain analysis as a microscopic diagnostic feature in the identification of plant material. Economic Botany 48 (2): 171-81. Crowther, A. 2012 The differential survival of native starch during cooking and implications for archaeological analyses: a review. Archaeological and Anthropological Sciences 4 (3): 221–235. French, D. 1984 Organization of starch granules. In Starch: Chemistry and Technology, edited by R. Whistler, J. BeMiller and E. Paschall, pp. 183-247. Academic Press, Florida. Fullagar, R. 2006 Starch on artifacts. In Ancient starch research, edited by R. Torrence and H. Barton, pp. 177-204. Left Coast Press, Walnut Creek. Gong, Y., Y. Yang, D. K. Ferguson, D. Tao, W. Li, C. Wang, E. Lüand and H. Jiang 2011 Investigation of ancient noodles, cakes and millet at the Subeixi Site, Xinjiang, China. Journal of Archaeological Science 38: 470-479. González, M. I. and M. M. Frère 2004 Analysis of potsherd residues and vessel use in hunter-gatherer-fisher groups (Pampean region, Argentina). In Proceedings of the XIV UISPP Congress, pp. 27-36. BAR International Series 1270, Archaeopress, Oxford. Hart, D. M. 2003 The influence of soil fauna on phytolith distribution in an Australian soil. In Phytolith and starch research in the Australian-Pacific-Asian regions: the state of the art, edited by D. M. Hart and L. A. Wallis, pp. 83-91. Terra Australis 19, The Australian National University, Canberra. Hart, T.C. 2011 Evaluating the usefulness of phytoliths and starch grains found on survey artifacts. Journal of Archaeological Science 38: 3244-3253. Haslam, M. 2004 The decomposition of starch grains in soils: implications for archaeological residue analyses. Journal of Archaeological Science 31: 1715-1734.

51

2006 An archaeology of the instant? Action and narrative in archaeological residue analyses. Journal of Social Archaeology 6 (3): 402-424. Henry, A. G., H. F. Hudson and D. R. Piperno 2009 Changes in starch grain morphologies from cooking. Journal of Archaeological Science 36: 915-922. Humphreys, G. S., D. M. Hart, N. Simons and R. J. Field 2003 Phytoliths as indicators of process in soils. In Phytolith and starch research in the Australian-PacificAsian regions: the state of the art, edited by D. M. Hart and L. A. Wallis, pp. 93-104. Terra Australis 19, The Australian National University, Canberra. ICSN 2011 The International Code for Starch Nomenclature, http://www.fossilfarm.org/ICSN/Code.html (accessed 19/10/2011). Jacobson, M. R., M. Obanni and J. N. BeMiller 1997 Retrogradation of starches from different botanical sources. Cereal Chemistry 74: 511-518. Jones, P. J. 2009 A microstratigraphic into the longevity of archaeological residues, Sterkfontein, South Africa. In Archaeological science under a microscope. Studies in residue and ancient DNA analysis in honour of T.H. Loy, edited by M. Haslam, G. Robertson, A. Crowther, S. Nugent and L. Kirkwood, pp. 29-46. Terra Australis 30, Australian National University E-Press, Canberra. Juan-Tresserras, J. 1992 Procesado y preparación de alimentos vegetales para consumo humano. Aportaciones del estudio de fitolitos, almidones y lípidos en yacimientos arqueológicos prehistóricos y protohistóricos del cuadrante NE de la Península Ibérica. PhD Dissertation, Universitat de Barcelona. Korstanje, M. A. 2003 Taphonomy in the laboratory: starch damage and multiple microfossil recovery from sediments. In Phytolith and starch research in the Australian-PacificAsian regions: the state of the art, edited by D. M. Hart and L. A. Wallis, pp. 105-118. Terra Australis 19, The Australian National University, Canberra. Korstanje, M. A. and M. P. Babot 2007 Microfossils characterization from south Andean economic plants. In Plants, people and places: recent studies in phytolith analysis, edited by M. Madella and D. Zurro, pp. 41-72. Oxbow Books, Cambridge. Langejans, G. H. J. 2010 Remains of the day-preservation of organic microresidues on stone tools. Journal of Archaeological Science 37: 971-985.

52

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

Lantos, I., M. Maier and N. Ratto 2012 Recreando recetas: primeros resultados de una experimentación con variedades nativas de maíz del Noroeste argentino. In Las manos en la masa. Arqueologías, antropologías e historias de la alimentación en Suramérica, edited by M. P. Babot, M. Marschoff and F. Pazzarelli, pp. 527-552. Instituto de Arqueología de Córdoba and Instituto Superior de Estudios Sociales, CONICET, Córdoba.

Musaubach, M. G. and M. A. Berón 2012 Cocinando en ollas en la Pampa Occidental. Datos desde la etnohistoria, el registro arqueológico y la arqueobotánica. In Las manos en la masa. Arqueologías, antropologías e historias de la alimentación en Suramérica, edited by M. P. Babot, M. Marschoff and F. Pazzarelli, pp. 599-620. Instituto de Arqueología de Córdoba and Instituto Superior de Estudios Sociales, CONICET, Córdoba.

Lewarch, D. and M. O´Brien 1981 The Expanding Role of Surface Assemblages in Archaeological Research. Advances in Archaeological Method and Theory 4: 297-342.

Osterrieth, M., M. Madella, D. Zurro and M. F. Álvarez 2009 Taphonomical aspects of silica phytoliths in the loess sediments of the Argentinean Pampas. Quaternary International 193 (1-2): 70-79.

López, M. L., A. Capparelli and A. Nielsen 2011 Traditional post-harvest processing to make quinoa grains (Chenopodium quinoa var. quinoa) apt for consumption in Northern Lipez (Potosí, Bolivia): Ethnoarchaeological and archaeobotanical analyses.

Osterrieth, M., M. Fernández Honaine, F. Álvarez, N. Borrelli and L. Benvenuto 2013 Procesos tafonómicos y silicofitolitos en secuencias pedoestratigráficas y pedoarqueológicas de distintos ambientes en Argentina. In Anais do Museu Nacional-

Journal of Anthropological and Archaeological Science 3 (1): 49-70. Lovis, W. A., G. R. Urquhart, M. E. Raviele and P. Hart 2011. Hardwood ash nixtamalization may lead to false negatives for the presence of maize by depleting bulk δ13C in carbonized residues. Journal of Archaeological Science 38: 2726-2730. Loy, T. 1994 Methods in the analysis of starch residues on prehistoric stone tools. In Tropical archaeobotany: Applications and new developments, edited by J. Hather, pp. 86-114. Routledge, New York. Lu, T. 2003 The survival of starch residue in a subtropical environment. In Phytolith and starch research in the Australian-Pacific-Asian regions: the state of the art, edited by D. M. Hart and L. A. Wallis, pp. 119-126. Terra Australis 19, The Australian National University, Canberra. Lyman, R. L. 1994 Vertebrate taphonomy. Cambridge Manuals in Archaeology, Cambridge University Press, Cambridge. Messner, T. and B. Schindler 2010 Plant processing strategies and their affect upon starch grain survival when rendering Peltandra virginica (L.) Kunth, Araceae edible. Journal of Archaeological Science 37: 328-336. Musaubach, M. G. and M. P. Babot 2014 Uso de las plantas entre los cazadores-recolectores pampeanos: estudio de microfósiles recuperados de tártaro dental humano, sitio Chenque 1. In El sitio Chenque. Un cementerio prehispánico en la Pampa Occidental. Estilo de vida e interacciones culturales de cazadores-recolectores del Cono Sur Americano, edited by M. Berón. Sociedad Argentina de Antropología, Buenos Aires, in press.

UFRJ, Serie Livros 49: 218. Resúmenes del 5º Encontro Latinoamericano de Fitólitos. Rio de Janeiro. Pardo, O. and J. L. Pizarro 2008 Alimentos: conservación y almacenamiento en el Chile Precolombino. Parina, Arica. Parr, J. F., G. Kerr, J. Arthur and K. H. Taffs 2008 Impact of fire on peatlands in northeastern NSW Australia: implications for the interpretation of microfossil assemblages and fire histories. In Matices interdisciplinarios en estudios fitolíticos y de otros microfósiles, edited by M. A. Korstanje and M. P. Babot, pp. 47-53. BAR International Series 1870, Hedges, Oxford. Pazzarelli, F. 2012 Arqueología de la comida. Cultura material y prácticas de alimentación en Ambato. PhD Dissertation, Universidad Nacional de Córdoba, Córdoba. Piperno, D. M. 1988 Phytolith analysis: an archaeological and geological perspective. Academic Press, San Diego. Pochettino, M. L. and M. C. Scattolin 1991 Identificación y significado de frutos y semillas carbonizados de sitios arqueológicos de la ladera occidental del Aconquija, Prov. de Catamarca, Rca. Argentina. Revista del Museo de La Plata (nueva serie) Antropología 9 (71): 169-181. Radley, J. A. 1943 Starch and its derivatives. 2nd. edition, Chapman and Hall, London. Raviele, M. 2011 Experimental assessment of maize phytolith and starch taphonomy in carbonized cooking residues. Journal of Archaeological Science 38 (10): 2708-2713.

Taphonomy in the kitchen: culinary practices and processing residues of native tuberous plants of the south-central Andes Reichert, C. T. 1913 The differentiation and specificity of starches in relation to genera, species, etc. Publication 173, Carnegie Institution of Washington D.C., Washington D.C. Samuel, D. 2006 Modified starch. In Ancient starch research, edited by R. Torrence and H. Barton, pp. 205-216. Left Coast Press, Walnut Creek. Tassara, G. and M. Osterrieth 2008 Silicofitolitos en artefactos de molienda de sitios arqueológicos del Área Interserrana, Buenos Aires. Un estudio preliminar. In Matices interdisciplinarios en estudios fitolíticos y de otros microfósiles, edited by M. A. Korstanje and M. P. Babot, pp. 163-171. BAR International Series 1870, Hedges, Oxford. Therin, M. 1994 Subsistence through starch: the examination of subsistence changes on Garua Island, West New Britain, Papua New Guinea, through the extraction and identification of starch from sediments. BA (Honours) Thesis, Sydney University, Sidney. Torrence, R. and H. Barton (editors) 2007 Ancient starch research. Left Coast Press, Walnut Creek. Wandsnider, L. A. 1997 The roasted and the boiled: food composition and heat treatment with special emphasis on pit-hearth cooking. Journal of Anthropological Archaeology 16: 1-48.

53

Whistler, R. L., J. BeMiller and E. Paschall (editors) 1984 Starch: Chemistry and Technology. Academic Press, Florida. Williams, M. R. and P. Bowler 1982 Starch gelatinization: A morphological study of Triticeae and other starches. Starch/Stärke 34: 221-223. Zucol, A. F. and D. M. Loponte 2008 Análisis comparativo metodológico y estudio de la abundancia fitolítica en tártaro de dientes humanos de sitios arqueológicos de la Pcia. de Buenos Aires, Arg. In Matices interdisciplinarios en estudios fitolíticos y de otros microfósiles, edited by M. A. Korstanje and M. P. Babot, pp. 39-45. BAR International Series 1870, Hedges, Oxford.

NOTES 1.- Resistant starch is defined as “[...] starch that is not digested in the small intestine of humans (Champ 2004; Biliaderis 2009). Useful term for explaining why some starches survive and others do not” (INSC 2011). In this paper, we used the term generically to refer to any starch grain preserved virtually unchanged. 2.- We consider charring as a special cooking technique used in ritual performances (e.g., in feeding Pachamama) (Pazzarelli 2012).

54

M. P. Babot et al. - Intersecciones en Antropología - Special Issue 1 (2014) 35-53

|

55

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) Mónica Grosso Received 21 August 2013. Accepted 20 February 2014 ABSTRACT The HMS Swift was a British Navy sloop-of-war that sank off the Patagonia coast in 1770. The Swift shipwreck site, on the northern coast of Santa Cruz Province (Argentina), is a well-preserved underwater archaeological site. The high frequency of wooden artifacts at the site permitted the development of specific research designed to identify the primary natural and cultural post-depositional processes related to the preservation and spatial distribution of those artifacts. This paper presents the methodological framework for this research, which included both direct observations and experimental studies that led to the characterization of the organisms related to the shipwreck site and their interaction with archaeological materials. Results confirm that sedimentary conditions have played a central role in the preservation of wooden materials and their spatial distributions. Furthermore, the archaeological consequences of organisms’ damaging activities (mainly those of marine wood-borer mollusks) are assessed. Keywords: Wooden artifacts; Post-depositional processes; Shipwrecks; Underwater archaeological sites; Patagonia. RESUMEN ESTUDIOS DE PROCESOS POSDEPOSITACIONALES EN ARTEFACTOS DE MADERA DEL SITIO DE NAUFRAGIO SWIFT, SIGLO XVIII (PATAGONIA, ARGENTINA). En los ambientes subacuáticos marinos, bajo ciertas condiciones, puede preservarse una diversidad de materiales arqueológicos de origen orgánico e inorgánico. Uno de estos casos es el sitio Swift, embarcación de la Armada Británica que en 1770 naufragó en la costa norte de la actual provincia de Santa Cruz. La existencia de una gran cantidad de artefactos de madera brindó una interesante oportunidad para realizar investigaciones dirigidas a identificar los principales procesos posdepositacionales de índole natural y cultural involucrados en la preservación y en la distribución de estos materiales. En este trabajo se presenta el enfoque metodológico aplicado, el cual incluyó la realización de observaciones y estudios experimentales que permitieron caracterizar las comunidades de organismos asociados al sitio y su interacción con los materiales arqueológicos. Los resultados obtenidos confirman que las condiciones sedimentarias han desempeñado un rol fundamental para la preservación de los materiales y sus relaciones contextuales. Asimismo, se analizan las consecuencias arqueológicas de la actividad de organismos que ejercen una acción destructiva, entre los que se destacan los moluscos marinos perforantes de madera. Palabras clave: Artefactos de madera; Procesos posdepositacionales; Naufragios; Sitios arqueológicos subacuáticos, Patagonia.

Mónica Grosso. Instituto Nacional de Antropología y Pensamiento Latinoamericano (INAPL). 3 de Febrero 1378 (1426), Ciudad de Buenos Aires, Argentina. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 55-69. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

56

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69 INTRODUCTION

LOSS OF THE HMS SWIFT

Since the development of underwater archaeology as a scientific discipline in the 1960’s, interest has increased in the factors that regulate differential preservation of shipwreck sites. In 1978 Keith Muckelroy proposed a pioneering model based on systematic research, which was later expanded upon by Ward et al. (1999) and Gibbs (2006). To date, most such studies have aimed to understand general processes involved in site formation and factors that contribute to in situ preservation of sites. Nevertheless, researches designed to improve our interpretations of the submerged archaeological record are still scarce (Grosso 2008, 2011). This situation can likely be explained by the common perception of shipwrecks as “time capsules”. Contrary to this perception, though, it has been argued that research must take into account the social and technological biography of ships as well as their contents, that is to say, their temporal depth (Adams 2001). Moreover, it should be noted that the loss of a ship is a process that can last many hours or even days. Therefore, even at shipwreck sites that appear to contain wellpreserved materials and to display original relationships between objects, the coherence and integrity of the context should not be assumed but archaeologically demonstrated (Adams 2001).

The Swift was a Royal Navy sloop-of-war stationed at Port Egmont, the 18th century British naval base in the Malvinas / Falkland Islands. Like all sailing ships at the time, the Swift was a wooden vessel. She had two decks, a length of 27.8 m and a breadth of 7.9 m (National Maritime Museum, Greenwich, NMM Draughts Box 52 N° 3603A ‘sheer and profile’, Swift and Vulture).

South America has also produced few studies on wrecksites formation processes; shipwreck archaeology in the region −with the exception of Argentina, Chile and Uruguay− is a field of study only now getting underway (Elkin 2011). In Argentina, archaeological research at the wreck site of the HMS Swift has included a multidisciplinary study of natural site formation processes from the beginning (Bastida et al. 2004; Elkin et al. 2011). As part of my doctoral research –which focused on wooden material culture onboard the Swift– I analyzed the primary natural and cultural post-depositional processes that affected the preservation and distribution of wooden artifacts (Grosso 2011). Here, I summarize the methodological approach and main results of that study. Additionally, I hope it will contribute to provide information relevant to the interpretation of other shipwreck sites located in the region’s underwater or intertidal marine environments.

In March of 1770, the Swift was stranded on a rock off the coast of Puerto Deseado estuary. Several measures were taken to avoid sinking1 but, eventually, the ship slipped away from the rock and sank. Very few items could be saved before the ship disappeared below the water (The National Archives, Kew, ADM 1/5304 Court Martial: Loss of HMS Swift, 29 September 1770; Gower 1803).

THE SWIFT ARCHAEOLOGICAL PROJECT The wreck site is located in the harbor of present day Puerto Deseado city, in northeast Santa Cruz Province, Argentina (Figure 1). Archaeological research at the site was begun in 1997 by the Programa de Arqueología Subacuática (Underwater Archaeology Program, or PROAS) of the Argentinean Instituto Nacional de Antropología y Pensamiento Latinoamericano (INAPL), under the direction of Dr. Dolores Elkin. To achieve the project’s research goals, survey of visible structural remains and excavation of representative sectors of the ship were planned (Elkin et al. 2007, 2011).

Figure 1. Location of the Swift wreck site in the harbor area of Puerto Deseado (Map: C. Murray).

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) The ship remains cover an area of approximately 180 m2. About 70% of the hull has survived, most still assembled, though sediments cover nearly 60% (Murray et al. 2003). The site is between 10 and 18 m below surface, depending on the bottom slope and level of the tide. The shallowest depth corresponds to the bow-starboard area, and the deepest to the stern-port. The hull lies on its port side with a list of about 60 degrees, such that the starboard side is the most exposed structural portion. While the port side of the upper deck is well preserved, the opposite side has collapsed or disappeared, with some frames and beams protruding up to 3 m above the sediment level. Neither masts nor yards were preserved (Figure 2). Many detached structural components, as well as cannons, anchors and a great diversity of organic and inorganic artifacts lie partially or totally covered by the sediments. Nearly all exposed elements are colonized by a variety of organisms, with the exception of those

57

scrambling devices. Extracting filters are processes that result in the loss of materials: elements floating away during the sinking, salvage operations, and disintegration of perishables. Scrambling devices are processes that move artifacts around, resulting in the loss of contextual information: the wreckage process, movement of the seabed (which may or may not bury elements), wave action, currents, and biological activity. Based on Muckelroy’s proposal, Ward et al. (1999) produced an expanded model that distinguishes the primary processes affecting disintegration of a shipwreck on the basis of the ship’s own characteristic, the sedimentary environment, and the hydrodynamic environment (Figure 3). The nature of the sedimentation process −whether it is accumulative or erosive− is considered the main factor in the shipwreck preservation, which, in turn, depends on sedimentary and hydrodynamic characteristics.

Figure 2. Site plan with the excavated areas highlighted (Drawing: C. Murray).

materials that may be toxic for them (like copper and copper alloys). Twenty six percent of the more than 500 artifacts retrieved from the site since its discovery were made of wood. These materials are currently housed at the Museo Municipal Mario Brozoski, Puerto Deseado2.

SHIPWRECK SITES FORMATION PROCESSES Muckelroy’s model of shipwreck site formation processes take into account the different components that contribute to the evolution of a shipwreck, from the time the ship was sailing to the presently-observed seabed distribution (Muckelroy 1978). He identified two main processes that operate during that timeframe: extracting filters and

Figure 3. Muckelroy’s expanded model. a) The wreck, b) the sedimentary environment, and c) the hydrodynamic environment. After Ward et al. (1999: 564).

58

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

Physical, chemical and biological processes are involved in the disintegration of a shipwreck, so it is important to identify and understand the dynamics of their interaction. Positive and negative feedback operate continually between the water, the sediment, and the wreck. In general, physical deterioration processes dominate in the early stages. Afterwards, as the shipwreck disintegrates and materials interact with the sedimentary environment, biological and chemical processes become relatively more important. In this model, the rate of shipwreck disintegration is equal to the sum of the rates of disintegration caused by physical, chemical and biological processes, in relation to the depositional history (that is, variation in sedimentary processes through time). The combination of these factors defines different possible levels of preservation (Ward et al. 1999).

BIODETERIORATION STUDIES IN MARINE ENVIRONMENTS Marine environments have great biodiversity and a remarkable variety of colonization modes may develop in them. Solid marine substrates can be divided into two groups: soft or sedimentary bottoms and hard or rocky bottoms, each with species living in close association with them (Bastida et al. 2004, 2008). Sedimentary bottoms prevail in nature and, therefore, a great demand exists for colonization of hard bottoms by organisms that need hard substrata to live. Consequently, when anthropic material is submerged in seawater it is immediately colonized by organisms, providing that it is not toxic for them. Among organisms that live in the sea, two main groups have been considered responsible for the most serious damage to man-made substrata: marine wood-borers, and biofouling (benthic communities associated to artificial substrata). These micro- and macro-organisms are capable of physico-chemical modification of materials as a result of their attachment to them (mechanical effects) and their metabolic processes. The search for methods to prevent the settling and harmful effects of biofouling has led to the development of biodeterioration studies as a specific field of research. Since the 1960s, Argentina has been a Latin American leader in this discipline. Studies on the experimental ecology of benthic communities have played a substantial role in biodeterioration research developing experimental systems to achieve controlled studies of the biological communities associated with diverse materials (see references in Bastida et al. 2004; Grosso 2008). Therefore, these studies provide basic information on the biological and ecological processes involved in the formation of underwater archaeological sites.

Marine wood-borers There are two groups of wood-borers in marine environments: mollusks and crustaceans. Bivalve mollusks are represented by two families: Teredinidae (“shipworms”) and Pholadidae (“piddocks”). Teredinidae is the larger group and is composed of a number of genera and species distributed around the world (but note that Teredo is often −and erroneously− referred to as the only genus). As soon as Teredinidae larvae find a suitable substratum, they begin to bore tunnels into the wood. Larvae gradually develop a soft, worm-like body with two valves at the front extremity that enable them to bore wood. As Teredinidae grow, they deposit a calcareous lining in the tunnel where they remain throughout their lives. A pair of siphons is the only part of the body that maintains contact with the seawater through the initial hole. A couple of calcareous pallets allow organisms to seal the hole when necessary. These elements enable taxonomic identification of species. As a consequence of the teredinids’ activity, a piece of wood can be completely bored inside while externally only the small initial holes of 1 to 2 mm in diameter are visible (Eaton and Hale 1993). Tunnels only become exposed when a piece of wood is broken or its surface heavily deteriorated. Pholadidae is a smaller group of mollusks than the Teredinidae and their geographical distribution is more limited. They also have a less significant role as destructive agents (Pournou 1999). Not all members of the Pholadidae family are exclusively wood-borers. Generally, they can be distinguished easily from the teredinids because they lack the characteristic wormlike body (with the exception of Xylophaginae) and do not create a calcareous lining in the tunnels walls. They have oval valves similar to those of the common clam but with a denticulate area for boring wood. Their tunnels can be 3 to 8 times the size of the valves (Eaton and Hale 1993). Marine wood-borer crustaceans are represented by the orders Isopoda and Amphipoda. The first includes the most important groups: Limnoriidae (“gribble”) and Sphareomatidae (“pill bug”). These organisms have small, segmented bodies −generally 2 to 4 mm long− and legs, so they are capable of moving over the wood surface. They produce superficial or subsuperficial galleries of 1 to 3 mm in diameter. The extensive network of galleries can lead to collapse of the superficial levels of the wood and, eventually, total destruction of the substratum. Teredinidae mollusks have been recorded off the coasts of Buenos Aires, Chubut (Puerto Madryn) and Tierra del Fuego (Ushuaia) Provinces, and the Malvinas / Falkland Islands. Limnoriidae are reported only in the first three localities (Bastida and Torti 1972a, 1972b; Prosser Goodall 1978).

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) Biofouling communities Contrary to what happens with wood-borers, few studies have been designed to understand the formation and development of biofouling communities in wreck sites (Thomson 1997; Randell 1998). This is remarkable in light of the fact that marine wreck sites develop into reefs of artificial origin. When an artificial substratum is submerged in seawater a biotic colonization process begins, which leads to the development of a biofouling community. This “benthic succession process” begins with the adsorption of organic macromolecules, followed by the formation of an initial biofilm constituted mainly by bacteria and micro algae, and continues with the settling and growth of different species of invertebrates and macro algae that form communities of variable complexity and ecological characteristics. The process tends to conduct the community to a final, equilibrium stage known as the “climax stage”, after which the detachment and partial restart of a new cycle takes place (Bastida et al. 2008). Biofouling in different parts of the world involves nearly 2000 micro- and macro-organisms (Florian 1987) and comprises aerobic bacteria, fungi, protozoa, diatoms, algae, bryozoans, coelenterates, polychaetes, mollusks and tunicates, among others. The diversity and variety of organisms differs according to the community stage of development and to local environmental conditions. Biofouling species can be sessile −attached to the substratum throughout its life by means of different mechanisms− or non-sessile.

POST-DEPOSITIONAL PROCESSES AT THE SWIFT SITE: GOALS AND METHODOLOGY The goal of this research was to identify the primary processes responsible for the differential preservation of wooden artifacts, as well as those that modified the artifacts’ original depositional context. The wooden artifacts database contains 197 objects from superficial sediment levels and excavation areas, and includes multi-component and singlecomponent artifacts, both complete and fragmented. The following functional categories were identified: tableware, cooperage, rigging, storage, tools, furniture, objects related to military or navigation activities, as well as unidentified elements. In each case the following data were recorded: provenience, general characterization, components (including other materials), and taxonomic identification when possible (Grosso 2011)3. To understand natural formation processes, prevailing environmental conditions at the site were

59

considered with a focus on hydrological and sedimentological parameters. Systematic sampling was performed to record sediment characteristics by means of three transects along the ship’s length, each with five sampling stations. The following data were collected: qualitative and quantitative fractions, granulometric classification, concentration of organic matter, concentration of calcium carbonate, and relative amounts of bioclasts and faunistic groups represented (Bastida et al. 2004, 2011). Afterward, a macroscopic examination of a sample of artifacts was conducted for the purpose of identifying the primary associations between different organisms and specific archaeological substrata, along with the consequences of these associations on the archaeological materials. The analysis included both in situ and recovered artifacts; the depositional context and general state of preservation were also considered. Excavated areas allowed the examination of wooden elements that had been covered by sediments. As shown in Figure 2, 20 m2 were excavated, distributed as follows: on the main deck near the galley (bow-port side) and the Captain’s quarters (stern-port side); on the lower deck, in a possible block storeroom, and forward of the main mast. In the two first areas listed, internal planking was reached while the others were just partially excavated. Additionally, an experimental study was performed to obtain controlled information about biofouling communities and wood-boring organisms, including their basic ecological and biological characteristics (Bastida et al. 2004). This study was adapted from others previously carried out in biodeterioration research in Argentina (Bastida et al. 2008, see references therein). The experimental design used acrylic and pine wood panels of 10 x 5 cm fitted to acrylic frames of 30 x 40 cm. Samples were taken at 6 (cold and warm seasons), 12 and 24 months to monitor seasonal cycles of colonization, growth and successional strategies of the community. Additionally, panels of 12 x 12 cm composed of thin wooden layers were used to obtain complete wood-borer specimens. The frames were located at the bow and stern areas of the vessel. Biological and sedimentary analyses were carried out by the Laboratorio of Ecología Bentónica y Biodeterioro (Benthic Ecology and Biodeterioration Laboratory) of the Mar del Plata National University, under the direction of Dr. Ricardo Bastida. Finally, to assess cultural formation processes, diverse sources of information were analyzed with the purpose of understanding the human activities that would have affected the site over the course of more than two hundred years.

60

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69 ENVIRONMENTAL CONDITIONS

The Deseado estuary is 40 km long, depending on the marine influence, and up to 400 m wide. Its maximum depth is 32 m, near the entrance, while its minimum is 0.5 m, at the end of the estuary. The Swift site is situated off the north coast of the estuary and near its mouth, such that the hydrological parameters are similar to those of the adjacent open sea. Marine water in this area is renewed in a high frequency due to the influence of the tides (Kühnemann 1971). Average annual salinity is 33‰ (typical ocean waters are 35‰), and Ph values are slightly alkaline −characteristic of seawater− ranging between 7.8 and 8.2. Dissolved oxygen values vary between 7.85 and 9.56 mg/l and slightly lower in areas with anthropic impact. The water temperature ranges between 13º C (summer) and 4º C (winter) (Elkin et al. 2007). Estuary tides are semi-diurnal; that is, two high tides and two low tides each day. They reach amplitudes of 4.2 m (average spring tides) so the estuary is considered a macro-tidal environment. This causes displacement of huge masses of water, which generates currents of up to 6 knots in narrow zones, though their speed decreases in some places according to topographic characteristics. Maximum currents at the site are about 2 knots. Waves have limited impact on the site; their maximum amplitude is 0.7 m. Prevailing winds are from the west and southwest and are generally strong (Kühnemann 1971). Underwater visibility is typically low, ranging from 0.1 to 2 m, with an average of 1 m. The low water transparency, and consequent limited light penetration, is caused by suspended sediment. Precipitation is scarce and without strong seasonal variance, with monthly values ranging from 5 to 45 mm. Sediment sampling at the site revealed a dominance of fine fraction sediments, with a significant presence of clay, mud, and fine sand (Figure 4). These small particles have a continental origin; they are swept by the rain towards the estuary. Coarse sands are very little represented, as are larger fractions, with the exception of some areas where a relevant abundance of granules and pebbles was observed (Bastida et al. 2011). The sediment composition has contributed to the formation of low oxygen level deposits. The considerable quantity of organic material that cannot be mineralized due to of the lack of oxygen generates hydrogen sulphide, easily detected by a pervasive, characteristic smell and the black coloration of the sediment. Negative Redox potential values (ranging from -140 to -314) confirm the anoxic nature of the burial environment. Concentrations of organic material reach high values of up to 9.02%. This is due to the high productivity of the water and benthonic communities, as well as the significant contributions

of the local harbor and its industrial fishery (Bastida et al. 2004, 2011).

SYSTEMATIC OBSERVATIONS AND EXPERIMENTAL STUDIES Systematic macroscopic observations have permitted an assessment of the more conspicuous association of biofouling and wood-borer communities with archaeological substrata. Type of material, shape and superficial texture, context of provenience, and primary features regarding their state of preservation (e.g., structural weakness, marine erosion) were recorded in each case. To gain a better understanding of biological communities associated with wood artifacts, it was also relevant to compare what happens to wooden ships’ structural elements, as well as to artifacts made on other materials. Primary associations are summarized in Table 1 (Elkin et al. 2007; Grosso 2008). In each case, levels of biodiversity and biomass are identified. Both refer to the natural communities of the area, which are considered the maximum level of biomass and biodiversity possible. Among the fouling organisms colonizing the shipwreck, tunicates (“sea squirts”) are the most notorious, due to their size and distribution over the whole site on various types of substrata. Tunicates are able to develop communities of considerable size even from very small areas, chiefly in zones of good water flow, as in the case of frames and beams that are nearly vertical due to the ship list (Figure 5).

Figure 4. Granulometric composition of the Swift site. Sizes classification follows Udden-Wentworth scale (Bastida et al. 2011).

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina)

MATERIALS

GLASS

Substrate surface

Fouling association (assemblages)

Smooth surfaces (bottles)

Associations represented by several invertebrates groups

Rough surfaces (windows emery glass panels)

Associations represented by several invertebrates groups and chordates

Ship structural components (beams and frames)

Associations represented by algae, invertebrates and chordates

Biodiversity (B1) and Biomass (B2) levels B1: Medium B2: Low B1: High B2: Medium B1: Medium B2: High

61

kelp (Macrocystis pyrifera) detached from nearby seabottoms are transported to the site by currents. They can reach 30 m of length and frecuently become tangled in structural timbers.

Small size wooden artifacts, such as blocks B1: Low Small artifacts over Associations represented by several and pulleys, present the sediment (pulley) invertebrates groups B2: Low comparatively minor species B1: High Associations represented by algae Iron and invertebrates diversity relative to structural B2: Medium METAL components and other Represented by only one invertebrate B1: Low Lead group B2: Low substrata, such as glass of rough surfaces and iron; small Table 1. General characterization of the biofouling associated to diverse substrata. coelenterates (anemones Corynactis carnea) and arborescent briozoans (e.g., Hippotoa bouganvillei) predominate. WOOD

Regarding biofouling effects on archaeological elements, it was observed that with the detachment of tunicates from wooden substrates, part of the woody tissue was also removed. Likewise, the activity of small organisms may have deleterious consequences, such as the impressions left by soft tubeworms (polichaetes) such as Platynereis australis (Figure 6a) or gastropod mollusks, as is probably the case with Crepidula dilatata. On the other hand, a positive outcome of biofouling organism growth might be that they provide a physical barrier against the abrasion produced by sediment transport (Thomson 1997; Jones 2003). Biofouling might also play an important role in preventing the settlement of wood-borers’ larvae (Nair and Saraswathy 1971; Pournou 1999).

Figure 5. Deck beams colonized by tunicates of solitary and colonial species (Photo: S. Massaro).

More conspicuous tunicates are from solitary species (e.g., Cnemidocarpa verrucosa, Molgula sp., Paramolgula gregaria, Ciona sp. and Corella eumyota) and colonial species (e.g., Sycozoa gaimardi, Amaroucium sp., Didemnum sp., Polyzoa opuntia). In the structural timbers mentioned above, there are also abundant small (Corynactis carnea) and large species of anemone (“sea anemones”). Species of red algae (Rhodymenia sp. and Ceramium sp.) and brown algae (Dyctiota sp.) are present, although in small amounts due to light limitations. Specimens of giant

Low visibility and biofouling organism coverage complicated the examination of wood-borer activity on archaeological materials in situ, which necessitated removal of organisms at specific points. Colonization was easily identified in ship structure timbers with minor biofouling coverage and with tunnels exposed on the bow’s main deck in the galley area, middle lower deck, and stern’s main deck forward of the mizzen mast, and bulkheads. Their activity was also identified in wood remains on the sediment surface at the bow and port side-stern areas. The morphology of the tunnels was consistent with those of teredinid mollusks species. On the other hand, a survey of more than one hundred artifacts (n = 140) from excavated and seafloor surface contexts indicate that at least 15% had been colonized by wood-borers. This may be a conservative estimate, however, since the assessment was performed with the naked eye (Grosso 2008). More than 50% of these artifacts (including chests, boxes, furniture, etc.) were not in contact with seawater before Swift sank. Borer tunnel morphology was also indentified as

62

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

teredinids, with one exception, which was assigned to the Pholadidae family (Bastida et al. 2004). This is consistent with the fact that their members colonize wood occasionally. Diameters of Teredinidae tunnels at the Swift site are between 4 mm and 15 mm. Larger diameters are due to erosion processes. Wood-borers burrows were observed in high densities, even in some small artifacts, with a length that in some cases exceeds 20 cm (Figure 6b). Different wood species were colonized including Ulmus sp. (elm), Quercus sp. (oak) and pinaceae. While no living wood-borers were found, the presence of calcareous pallets permitted identification of Bankia martensi, previously documented in some parts of the Argentinean coast, but not in the Puerto Deseado area (Bastida and Torti 1972a). The experimental study provided valuable information regarding identification and characterization of the biofouling community structure. Analysis of the 6-, 12- and 24-month panels included a description of biofouling organisms examined under a stereoscopic microscope. Primary species were identified and quantified, and their maximum density and biomass calculated (see Grosso 2008 and Elkin et al. 2011 for detailed information regarding methods and results). The activity of wood-borers was also considered. The results indicate that biofouling communities have a similar composition to those observed in other Patagonian localities (Bastida et al. 2004). Despite low water temperatures, they are present throughout

the year, though the warm season is characterized by increased colonization activities and growth rates. Indeed, warm months show greater taxonomic diversity and higher biomass (triple as a minimum) than cold months. The climax stage -when communities reach a balance and achieve their maximum development- is dominated by colonial species of tunicates Paramolgula gregaria and Cnedomicarpa verrucosa. These communities can evolve considerably, developing more than 10 cm of thickness on 10 x 5 cm panels (Figure 7). Given that other environmental parameters remain the same all year round, this study reveals that water temperature is the main factor regulating growth and development of biofouling organisms. Wood panels host higher biomass than acrylic ones, probably because organic material offers a more suitable surface for colonization, especially in its early stages. On wood panels, biodeterioration was mainly produced by bacteria, fungi and Foliculinidae (ciliated protozoans). The latter were able to perforate the substrata at a superficial level or settle in its natural irregularities. No wood-borer activity (neither mollusk nor isopods) on wooden panels was observed under the stereomicroscope during the two-year experimental study. Finally, a systematic survey of non-archaeological wooden substrata along more than 5 km of the Deseado estuary’s north coast was designed to evaluate historical and present day wood-borer activity in the area. This included examination of an early 20 th century pier, wooden boats, and natural and anthropic wooden elements left by tides on the beach. Nearly a hundred wooden elements were observed, but only about 1% showed clear evidence of teredind activity. It should be noted that observed tunnels were eroded to a great extent indicating that the colonization was not recent.

CULTURAL FORMATION PROCESSES

Figure 6. a) Impressions left by soft tube polichaetes in chest components. b) Timber broken as a consequence of teredinids activity. One of the tunnels still retains its calcium carbonate lining.

Documentary, historical and oral information was used to identify anthropic activities that took place in the Swift site area between its sinking and the present to assess their role in site formation processes. Documentary sources explain how survivors of the wreck managed to rescue some objects (two officers’ chests and some spars) that floated away from the ship in the days after the sinking.

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina)

63

near the site, but a recent assessment during one of these operations indicated that it had no noticeable impact on the site (Elkin et al. 2011). Finally, interventions on the site must be considered. After discovery of the shipwreck in 1982, local divers retrieved nearly 180 artifacts. These materials all lack information about their Figure 7. a) Wooden panels after one year of immersion. b) Significant growth of biofouling precise location (Elkin et form one of the acrylic panels after two years of immersion. al. 2011). According to the divers’ reports, the artifacts were distributed on the Additionally, crew members dived into the wreck sediment surface or buried up to 50 cm, so their and managed to recover rigging elements and sails, extraction would have disturbed archaeological which were used to build tents (Gower 1803). After the contexts. Afterward, four field seasons were carried survivors left Puerto Deseado, no salvage operations out by the Argentinean Committee of the International or “opportunistic” recoveries (sensu Gibbs 2006) are Council of Monuments and Sites (ICOMOS), and one documented for the wreck site. The only historical season by Fundación Albenga. The main goal of these reference to such activity is the collection of rigging initiatives was to perform non-intrusive recording of elements that were found on the coast by Antonio the ship, and only few artifacts were recovered (Elkin de Viedma´s expedition in 1780, which probably et al. 2011). At that time, and also over the course of belonged to the Swift (Viedma [1837] 2006: 74-78). At subsequent archaeological work, divers’ displacement the time of the wreck, no permanent human settlement and equipment operation might have disturbed the could be found within hundreds of kilometers of the superficial layer of sediment. Likewise, artifacts and wreck. Until the end of the 18 th century, the only structural components of the ship, previously protected people inhabiting the adjacent land were nomadic by stable layers of sediments, became exposed at least indigenous groups. It is important to mention, however, temporarily during archaeological excavation activities. that Puerto Deseado is a natural harbor that has been frequently visited by vessels since the 16 th century. Although salvaging shipwreck remains used to be a common practice, available evidence suggests that it PRESERVATION AND DISTRIBUTION is possible the Swift remained virtually unknown below PROCESSES the water’s surface until recently. According to biodeterioration models, colonization In the 18 th and 19 th centuries few settlements by different microorganisms begins almost immediately were established along the estuary coast, until 1884 after a ship sinks. Enzymes secreted by fungi and when the town of Puerto Deseado was founded. At bacteria break down wooden cell walls (composed the beginning of the 20th century a pier for boats and mainly of cellulose, hemicellulose and lignin), causing small ships was operating near the wreck site. Large physical and chemical damage (Blanchette 2000). vessels could not come close to the shore due to their Non-biotic processes also take place, including draught, but the anchors of boats and small ships could hydrolysis, which usually occurs when the wood is have damaged the Swift. A local resident indicated that immersed in water, and causes decomposition of in this area anchors and fishing tackle often became molecules’ compounds (Pournou 1999). Furthermore, entangled (Elkin et al. 2011). This might have been abrasive sediment particles transported by currents can an important factor in the physical deterioration of erode artifacts (Jones 2003). In this way, the chemical the most exposed structural remains, like the bow and composition and microscopic structure of wood are starboard side. modified, making it more porous and permeable to th the water. In the last decades of the 20 century, Puerto Deseado evolved into one of the most active commercial Even if artifacts maintain their general shape, ports on the Patagonian coast. In the harbor, large changes in their structural tissue and external vessels are frequently towed between the wharf and appearance may occur. For example, some artifacts a dry dock; the Swift site is very near the tow path. It from the Swift site have polished edges caused by is likely that the movement of the propellers -some marine abrasion and others have a rough surface of them very powerful- affects the superficial levels due to biotic activity. Quite often, the second case is of sediment. Dredging is also occasionally performed

64

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

also associated with a significant loss of hardness and resistance; the wood becomes extremely soft (or spongy) at the slightest contact. Despite being fragile, artifacts’ general shape may remain unchanged because water and the remaining lignin -more resistant to degradation than cellulose- support its shape (Jones 2003).

thus inhibiting bacterial decay. This results in some coniferous species being more resistant to biodeterioration than some “hardwoods” (angiosperms). Nevertheless, as soon as those compounds leach out, these species become equally vulnerable to biodeterioration (Jones 2003).

The degree to which organisms can leave impressions on wood surfaces depends on both the way they associate with the substratum and the condition of the wood tissue. Therefore, if the artifact is significantly decayed, even minor organic activity might leave marks (Figure 6a). Furthermore, regarding the consequences of tunicate detachment, we must bear in mind the cumulative effects of continuous cycles of fixing, development, and detachment of organisms and communities over more than two hundred years. The potential loss of archaeological information caused by these factors must be considered. Based on observation of several artifacts from the Swift, such losses include features associated with the artifacts’ manufacture, use, or ownership (such as inscriptions and stamps; Grosso 2011).

In underwater environments wood permeability can be counteracted by the deposition of inorganic salts, calcareous materials, and the byproducts of metal corrosion, which, prevent its micro-structure from collapsing (Grattan 1987). This process depends on the chemical characteristics of the environment and the amount of time the artifacts have remained in that environment. This preservative effect has been observed in several artifacts from the Swift, typically boxes and a chest, which made possible to identify completely corroded elements (e.g., hinges and locks) that otherwise would not have been noticed.

The particular physical and chemical properties of different wood species are also relevant factors when considering the degradation and water-saturation processes in the marine environment. In this respect, it has been stated that porous woods like Betula sp. (birch), Fagus sp. (beech) and Fraxinus sp. (ash) become completely saturated within a few hours of being submerged and scarcely survive in the water. However, several artifacts manufactured with some of these species (i.e., Fagus sp. and Fraxinus sp.) were found at the Swift site. Additionally, objects made from Fagus sp exhibit clear differences in their preservation, likely due to differences in their depositional histories. For example, the most degraded artifacts (tableware pieces) were found in the galley area, a location more exposed than the stern, where well preserved objects (such as a shoe last) were found completely covered by sediments (Figure 8). It has also been noted that specific substances of certain wood species can be toxic for microorganisms,

Colonization by teredinid mollusk larvae may also have occurred in the first years following the wreckage. There is some evidence to support this such as artifacts in the lower excavation levels in the stern area that show signs of colonization. Furthermore, it takes time for the wood to be eroded enough to expose teredinid tunnels and to lose the internal carbonate, as was observed in some cases. It is likely that woodborer activity in the Swift began in the Malvinas / Falkland Islands, where Bankia martensi has been identified. Once the ship wrecked, colonization could have expanded to the entire shipwreck. The scarcity of wood-borer activity observed during the coastal survey supports the hypothesis that they are not a chronic problem in this area. Despite the fact that there is no clear evidence of teredind activity at present, colonization events may be cyclical through time, and their future presence at the site should not be dismissed (Elkin et al. 2011). In situ observations reveal that colonization has spread over structural elements and objects of varied forms and sizes, which supports arguments that different wood species and their hardness are not determining factors for wood-borer settlement (e.g., Nair and Saraswathy 1971; Bastida and Torti 1972a). It is interesting to note also that artifact size has no apparent relation to the intensity of colonization (Figure 6b).

Figure 8. A shoe last (INA 399) and a plate fragment (INA 471), both made from Fagus sp., exhibit differential preservation as a consequence of their particular post-depositional history.

C omparing the effects of different biodeterioration agents, marine borers have been said to produce the most severe damage in a relatively short amount of time (Gregory 1998). Tunnels create empty spaces in the wood, which increase its permeability

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) and structural fragility. This leads to a reduction in its density and mechanical resistance (Pournou 1999), which reduces the weight of wood objects and makes them more vulnerable to being displaced by currents. In turn, fungi and bacteria play a relatively minor role in the deterioration of marine archaeological wood, though they do affect their long-term preservation (Gregory 1998). At the Swift site, it was observed that artifacts more severely colonized by wood-borers were more prone to fragmentation. Small fragments are more susceptible to further biotic and abiotic deterioration. This is why, contrary to what happens with glass or ceramic fragments, wooden fragments tend to have a less significant diagnostic potential. The deposition of thin particles of sediment was a slow but constant process since the Swift sank, until a certain stability was reached. The wreck constitutes an obstacle that slows down tidal currents, acting as a sediment trap. The formation of an anoxic environment is beneficial to the preservation of archaeological materials, particularly organic ones, because the lack of oxygen prevents the development of most organisms, with the exception of specialized (anaerobic) bacteria. However it is worth noting that even a small portion of a wooden artifact that remains exposed it is enough for wood-borers to colonize the whole piece (Figure 9). In addition, sediment coverage also protects materials from the marine erosion produced by the sediment transportation of tidal currents.

65

already well developed (Bastida et al. 2004). There is no clear evidence of wood-borers on beams and frames, though they did colonize the decks planks, so may have played a role in structural collapse. The deterioration of structural boundaries like decks and bulkheads could have led to the dispersion of artifacts that had originally been retained in ship compartments. For example, those elements belonging to the missing sectors of the upper deck might have slipped towards the portside or collapsed together with that part of the ship, depending on their different attributes (e.g., material, dimensions, weight, and whether they were fixed or loose). At the stern excavation area (captains’ quarters), materials on the sediment surface or near it did not maintain a clear contextual association. Objects that seem to come from the collapsed starboard area were found there. The integrity of the objects themselves was poorly preserved. For these reasons, contextual associations should be interpreted with caution, particularly in the case of cupboards, chests and boxes and their possible contents. On the contrary, in the lower levels of the excavation, bulkheads have been largely preserved

As mentioned previously, the superficial stability of sediments can be modified by currents, archaeological work, and bioturbation produced by benthonic invertebrates, whose effects, while generally minor, can be cumulative and significant (Ferrari and Adams 1990). All of these factors can result in the exposure of archaeological materials to new oxygenated conditions, making them vulnerable to deterioration. Recording the structural remains provided a more comprehensive view of the possible processes and successive stages of the ship’s deterioration and, consequently, of the distribution and preservation of its contents. After the sinking, the elements that remained more exposed or closer to the water surface –the rigging, the bow and part of the starboard side– would likely have suffered the buffeting of waves and tidal currents, as well as the consequences of anthropic impact. In combination with this, the mechanical effects of the giant kelp Macrocystis pyrifera (Bastida et al. 2008) and large colonies of tunicates attached to the structural timbers could have further weakened them; according to the results of the experimental studies it is likely that, within one year of the wreck, macrofouling communities were

Figure 9. Part of this sea chest component was seriously deteriorated because of wood-borers activity and erosion processes. A well preserved area due to sediment coverage can clearly be observed (Photo: C. Murray).

66

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

and permitted the distinction between the Captain’s cabin and his chamber. The spatial location and the integrity of the objects there seemed more clearly defined. Some examples of this are furniture (e.g., folding stools) found in what it seems to be its original storage location, and a cupboard and its content that have maintained their contextual relations. Sediment accumulated inside boxes and chests before nails and ironwork corroded, preventing the collapse of wood components and preserving the original content. This pattern has also been observed in other areas of the site where sedimentation was rapid, even in levels close to the surface (Figure 10). The results obtained in these studies have been essential to discuss research questions related to material culture at the Swift site. This includes artifact provenience, function, and contextual associations; links between objects and crew members, and personal belongings versus navy property (see Grosso 2011, 2013).

CONCLUSIONS Regarding post-depositional processes affecting the Swift site, the essential factors affecting the survival

and distribution of archaeological materials are the environmental characteristics and their particular dynamics, even in those cases where human activity had a considerable influence. The integrity of materials is related to complex processes, which in turn depend on the depositional microenvironment and the physicochemical properties of the wood. As Ferrari and Adams (1990) indicate, it is important to approach this relationship not simply in terms of the environment influence on the archaeological materials, but as an interaction between them. The shipwreck process, the bottom slope, and the prevailing current direction have been the most important factors that determined the distribution of artifacts towards the portside and stern areas. The accumulation of sediment at the Swift site has been a major a control agent, facilitating the survival and integrity of the archaeological record. Teredinid mollusks have been the primary agent of biodeterioration, both in the aggressiveness of their action but also the rapidity of their colonization. Teredinids have played a fundamental role in the decay of wooden artifacts –resulting in partial or complete destruction– and also in their spatial distribution. Fouling organisms can also produce certain deleterious effects, particularly the loss of surface evidence in artifacts. The results obtained to date allowed us to understand preservational and distributional processes at different scales, from the site as a whole, to excavated areas and individual components. The research should continue as the excavation progresses in new areas. At present, the interventions at the site are temporarily suspended until further progress with stabilization treatments can be made at the conservation laboratory. In addition, the biotic and abiotic microdeterioration processes in wooden artifacts is an issue that still requires investigation at the site, both in terms of continued study of formation processes and in situ preservation assessment. This research field has not yet been pursued in Argentine Patagonian waters and in the future could be developed in the region based in the work carried out in the last years by several research projects (e.g., Pournou 1999; Jones 2003; Manders 2004; Palma 2004).

Figure 10. Medicine chest found on the superficial level in the amidhsip area with a very well preserved content (Photo: C. Murray).

Finally, the recovered data highlight aspects that must be taken into account when working at the site. The handling of wooden artifacts –underwater and on land– must be done with extreme care, even if the artifacts appear to be in a good

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) condition, since the structure of the wood could be very weak and therefore easily damaged. At the end of each fieldwork season, excavated areas must be covered (e.g., refilled with sediment) to avoid further colonization on newly oxygenated wood (see Gregory 1998, among others). Lastly, periodic monitoring of the site should be carried out. In light of the information obtained to date, a considerable contribution to understanding formation processes at the Swift site was achieved. This knowledge may also be relevant for building predictive models for the assessment of other sites less well preserved than the Swift, both in underwater and intertidal environments of the Argentine Patagonian coast.

Acknowledgements This research was only possible after many years of joint work. I am especially grateful to my PhD directors, Dr. Dolores Elkin and Dr. Ricardo Bastida, for their guidance and support. Dr. Bastida significantly contributed to the accomplishment of this research and has generously provided me with specialized bibliography. I would also like to thank all the people who have worked or assisted in the fieldwork and laboratory analyses, particularly the PROAS members and the team of the Laboratorio de Ecología Bentónica y Biodeterioro (Mar del Plata University), to Marilin Castro and Glenn McConnachie for wood anatomical identifications, and to the friends from Puerto Deseado who have generously provided their help through these years. Several institutions have supported the HMS Swift Project since it beginning: Fundación Antorchas, Secretaría de Cultura de la Nación, Municipalidad de Puerto Deseado, Museo Municipal Mario Brozoski, Gobierno de Santa Cruz and the British Embassy in Argentina. I would also like to thank Women Divers Hall of Fame for the Cecelia Connelly Memorial Scholarship in Underwater Archaeology, which I had the honor to receive. I gratefully acknowledge Cristian Murray and Alejandra Elías for their comments, and to the anonymous reviewers and the editors Karen Borrazzo and Celeste Weitzel for their valuable observations and suggestions to improve this work, as well as for translating the abstract. Thanks also to Ana Castelli for her assistance with the translation and to Raven Garvey for her helpful review of the English language that have improved the final manuscript.

REFERENCES Adams, J. 2001 Ships and boats as archaeological source material. World Archaeology 32 (3): 292-310.

67

Bastida, R. and M. R. Torti 1972a. Organismos perforantes de las costas argentinas. I. La presencia de Lyrodus pedicelatus (Quatrefages, 1849) (Mollusca, Pelecypoda) en el puerto de Mar del Plata. Clave para el reconocimiento de los Teredinidae sudamericanos. Physis 31 (82): 39-50. 1972b. Organismos perforantes de las costas argentinas. II. La presencia de Limnoria (Limnoria) tripunctata (Menzies, 1951) (Isopoda, Limnoriidae) en el puerto de Mar del Plata. Physis 31 (82): 143-153. Bastida, R., D. Elkin, M. Grosso, M. Trassens and J. P. Martin 2004 The British sloop of war HMS Swift (1770): a case study of the effects of biodeterioration on the underwater cultural heritage of Patagonia. Corrosion Reviews, Special Issue: Biodeterioration of Cultural Heritage 22 (5-6): 417-440. Bastida, R., M. Grosso and D. Elkin 2008 The role of benthic communities and environmental agents in the formation of underwater archaeological sites. In Underwater and Maritime Archaeology in Latin America and the Caribbean, edited by M. E. Leshikar-Denton and P. Luna Erreguerena, pp. 173-185. Left Coast Press, Walnut Creek. Bastida, R., M. Trassens, J. P. Martin and M. Grosso 2011 El papel de los sedimentos en la formación y conservación de los sitios arqueológicos subacuáticos: el caso de la HMS Swift (1770). In El naufragio de la HMS Swift (1770). Arqueología marítima en la Patagonia, Specialized Studies section coordinated by R. Bastida, pp. 27-57. Vázquez Mazzini, Buenos Aires. Blanchette, R. 2000 A review of microbial deterioration found in archaeological wood from different environments. International Biodeterioration & Biodegradation 46: 189-204. Eaton, R. A. and M. D. C. Hale 1993 Wood. Decay, pest and protection. Chapman & Hall, London. Elkin, D. 2011 Shipwreck Archaeology in South America. In The Oxford Handbook of Maritime Archaeology, edited by A. Catsambis, B. Ford and D. L. Hamilton, pp. 685707. Oxford University Press, Oxford. Elkin, D., A. Argüeso, M. Grosso, C. Murray, D. Vainstub, R. Bastida and V. Dellino-Musgrave 2007 Archaeological research on HMS Swift: a British Sloop-of-War lost off Patagonia, Southern Argentina, in 1770. The International Journal of Nautical Archaeology 36 (1): 32-58.

68

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

Elkin, D., C. Murray, R. Bastida, M. Grosso, A. Argüeso, D. Vainstub, C. Underwood and N. Ciarlo 2011 El naufragio de la HMS Swift (1770). Arqueología marítima en la Patagonia. Vázquez Mazzini, Buenos Aires. Ferrari, B and J. Adams 1990 Biogenic modifications of marine sediments and their influence on archaeological material. The International Journal of Nautical Archaeology and Underwater Exploration 19 (2): 139-151. Florian, M-L. E. 1987 The underwater environment. In Conservation of Marine Archaeological Objects, edited by C. Pearson, pp. 1-20. Butterworths, London. Gibbs, M. 2006 Cultural Site Formation Processes in Maritime Archaeology: Disaster Response, Salvage and Muckelroy 30 Years on. The International Journal of Nautical Archaeology 35 (1): 4-19. Gower, E. 1803 An Account of the Loss of His Majesty’s Sloop’Swift’, in Port Desire, on the Coast of Patagonia, on the 13th of March, 1770. Winchester and Son, London. Grattan, D. W. 1987 Waterlogged wood. In Conservation of Marine Archaeological Objects, edited by C. Pearson, pp. 5567. Butterworths, Londres. Gregory, D. 1998 Re-burial of timbers in the marine environment as a means of their long term storage: experimental studies in Lynæs Sands, Denmark. The International Journal of Nautical Archaeology 27 (4): 343-358. Grosso, M. 2008 Arqueología de naufragios: estudio de procesos de formación naturales en el sitio HMS Swift (Puerto Deseado, Santa Cruz). In Undergraduate thesis, Departamento de Ciencias Antropológicas II. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires (CD ROM). 2011 Estudios de cultura material en sitios históricos de naufragio en el litoral patagónico. El uso de la madera en artefactos del barco británico HMS Swift (siglo XVIII). PhD dissertation, Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2013 Qué llevar y cómo transportarlo. Acerca de los enseres de almacenaje en un barco de guerra inglés del siglo XVIII (Puerto Deseado, Santa Cruz). Intersecciones en Antropología 14: 157-170. Jones, M. (editor) 2003 For future generations. Conservation of a Tudor Maritime Collection. The Mary Rose Trust, Portsmouth.

Kühnemann, O. 1971 Vegetación Marina de la Ría de Puerto Deseado. Centro de Investigación de Biología Marina, Contribución Científica N° 30. Buenos Aires. Manders, M. 2004 Protecting Common Maritime Heritage. The Netherlands involved in two EU-projects: MoSS and BACPOLES. Mediterraneum 4, Protection and Appraisal of Underwater Cultural Heritage, edited by F. Maniscalco, pp. 279-292. Massa, Napoli. Muckelroy, K. 1978 Maritime Archaeology. Cambridge University Press, Cambridge. Murray, C., D. Elkin and D. Vainstub 2003 The Sloop-of-War HMS Swift. An archaeological approach. In The Age of Sail 1. The International Annual of the Historic Sailing Ship, edited by N. Tracy, pp. 101-115. Conway Maritime Press, London. Nair, N. B. and M. Saraswathy 1971 The biology of wood boring teredinid molluscs. In Advances in Marine Biology, Vol. 9, edited by F. Russel and M. Yonge, pp. 335-509. Academic Press, London and New York. Newsom, L. A. and R. B. Miller 2009 Wood Species Analysis of Ship Timbers and Wooden Items Recovered from Shipwreck 31CR314, Queen Anne´s Revenge Site. Research Report and Bulletin Series QUR-R-09-01. Queen Anne´s Revenge Shipwreck Project. Underwater Archaeology Branch, Department of Cultural Resources, State of North Carolina. Palma, P. 2004 Final Report for the Monitoring theme of the MoSS Project. Moss Newsletter Final Report: 8-37. The National Board of Antiquities. Pournou, A. 1999 In situ protection and conservation of the Zakynthos wreck. PhD Thesis. University of Portsmouth, School of Biological Sciences, Portsmouth. Prosser Goodall, R. N. 1978 Tierra del Fuego. Rae Natalie Prosser Goodall, Harberton. Randell, S. 1998 Marine growth on shipwrecks. The Bulletin of the Australian Institute for Maritime Archaeology 22: 107-108. Thomson, L. 1997 The biodegradation of the wreck Day Dawn. The Bulletin of the Australian Institute for Maritime Archaeology 21 (1&2): 119-124.

Post-depositional processes studies of wooden artifacts from the 18th century Swift shipwreck site (Patagonia, Argentina) Viedma, A. de [1837] 2006 Diario de un viaje a la costa de la Patagonia... desde el puerto de Santa Elena hasta la boca del Estrecho de Magallanes. In Diarios de Navegación. Expediciones por las costas y ríos patagónicos (1780-1783), directed by N. Tello, pp. 4598. Buenos Aires, Continente. Ward, I., P. Larcombre and P. Veth 1999 A New Process-based Model for Wreck Site Formation. Journal of Archaeological Science 26: 561-570.

69

NOTES 1.- A detailed analysis of this “response to shipwreck’s threat” (sensu Gibbs 2006) is in Elkin et al. (2011). 2.- Some of the Swift´s artifacts are at different stages of the conservation treatment. Once taken out of the water, wooden artifacts must be stabilized and dried in a controlled procedure (see Jones 2003, among others). 3.- The identification of wood taxonomy based on its anatomical characteristics has limitations because generally the possible taxonomic specificity reaches only the level of genus or subgenus. Also, the deterioration of the cell structure of the wood sample may inhibit or make difficult the identification (Newsom and Miller 2009).

70

M. Grosso - Intersecciones en Antropología - Special Issue 1 (2014) 55-69

|

71

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) Carlos Landa, Virginia Pineau, Emanuel Montanari and Jimena Doval Received 29 August 2013. Accepted 28 April 2014 ABSTRACT The Mariano Miró archaeological site (Chapaleufú Department, La Pampa Province, Argentina) was a town of nearly 500 inhabitants, founded in 1901 and abandoned in 1911. From the Historical Archaeology perspective, this paper aims to reconstruct the taphonomic histories of surface artifact assemblages from the Mariano Miró ghost town. We analyze taphonomic processes at both the artifact and the assemblage level, considering multiple variables including size, thermal alteration, weathering, site topography, trampling, anthropic activities and burrowing animal activities. We use GIS to interrelate the selected variables and assess the roles of various taphonomic agents in shaping the characteristics and distributions of materials at Mariano Miró. The information pertaining to formation processes obtained from Mariano Miró is potentially useful for generating expectations for and understanding other sites in the region that exhibit similar taphonomic conditions. Keywords: Mariano Miró; Ghost Town; Taphonomy; Historic Archaeology; GIS.

RESUMEN TAFONOMÍA DE UN PUEBLO: EL SITIO MARIANO MIRÓ DE PRINCIPIOS DEL SIGLO XX (DEPARTAMENTO DE CHAPALEUFÚ, LA PAMPA, ARGENTINA). El sitio Mariano Miró (departamento Chapaleufú, Provincia de La Pampa, Argentina) fue un pueblo de casi 500 habitantes fundado en 1901 y abandonado en 1911. Desde la perspectiva de la arqueología histórica, se propone reconstruir las historias tafonómicas del conjunto artefactual de superficie de este “Ghost town”. Los procesos tafonómicos son analizados desde la escala del artefacto y su distribución espacial considerando múltiples variables (tamaño, alteración térmica, meteorización, topografía del terreno, pisoteo, actividades antrópicas y animales cavadores). Se utiliza sistema de información geográfica (SIG) para interrelacionar las diferentes variables de análisis y evaluar la incidencia de los distintos agentes tafonómicos en las características y distribución de los materiales. Esperamos poder comprender la dinámica de formación que afectó al sitio y generar expectativas para contextos tafonómicos similares de la región. Palabras clave: Mariano Miró; Tafonomía; Arqueología histórica; “Ghost town”; GIS.

Carlos G. Landa. Instituto de Arqueología. Facultad de Filosofía y Letras, Universidad de Buenos Aires (FFyL, UBA). Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). 25 de Mayo 217 3° piso, of. 8 (1002), Ciudad Autónoma de Buenos Aires. E-mail: [email protected] Virginia Pineau. Instituto de Arqueología. FFyL, UBA. 25 de Mayo 217 3° of. 8 (1002), Ciudad Autónoma de Buenos Aires. E-mail: [email protected] Emanuel Montanari. Instituto de Arqueología. FFyL, UBA. 25 de Mayo 217 3° of. 8 (1002), Ciudad Autónoma de Buenos Aires. E-mail: [email protected] Jimena Doval. Instituto de Arqueología. FFyL, UBA. CONICET. 25 de Mayo 217, 3° piso, of. 8 (1002), Ciudad Autónoma de Buenos Aires. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 71-84. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

72

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84 INTRODUCTION

After the so-called “Conquest of the Desert” 1, thousands of hectares of productive lands in southwestern Buenos Aires Province, Argentina were incorporated to the national territory. This led to economic expansion and the consolidation of the Nation State, which in turn led to Argentina’s penetration of international markets (Oszlak 1997). Land was divided into lots and awarded to a small number of individuals, creating large latifundia. As different “social actors” -settlers, tenants, sharecroppers, migrant workers, farmers, merchants- began to occupy these spaces, the first rural villages developed. This process was accompanied by railway expansion that connected distant areas, peoples, ideas and merchandise. In this context, Mariano Miró began as a rural village in what, at that time, was the national territory of La Pampa; it was established by a train station of the same name in 1901 and abandoned in 1911. The present study contributes to our understanding of the dynamics of spatial occupation by the first tenants of villages in the current Pampean territory in the late 19th and early 20th centuries. Currently, the only traces of Mariano Miró are abundant artifacts on the surface of a vast area (ca. 32,900 m2), clear evidence that settlement attempts were not always successful. The remains of failed settlements constitute a significant part of the present regional identity. Many villages associated with capitalist production that, like Mariano Miró, were abandoned have been studied worldwide, contributing to an “Archaeology of abandonment” or “Archaeology of ghost towns” (Neville and Hooker 1997; Bell 1998; Vilches et al. 2008; Fuentes 2010; Lawrence and Davies 2010; Peyton 2012, among others). As a first approach to the site, and in order to assess the integrity and resolution of the surface record, we aim to reconstruct the taphonomic histories of surface remains (glass, pottery, metal, bone, earthenware, among others) (Binford 1981). We analyze taphonomic processes at both the artifact level and material distributions through space, and assess a number of variables including topography, object size, thermal alteration, weathering, agricultural activities, trampling, and the action of burrowing animals. Our use of geographic information systems (GIS) allowd us to interrelate different variables and evaluate the effects of taphonomic agents on the condition and distribution of surface materials. In addition, we used a host of documentary sources such as maps, population censuses, agricultural censuses, photos and oral story-telling to provide data for the investigation. By these methods, we hope to understand the formation dynamics that affected the site and to derive expectations for understandin other regional

sites with similar characteristics. Lastly, we hope the results of our taphonomic analysis will allow us probe social practices at the site such as those related to discard and cleaning during its occupation. Following Borrazzo, we take a taphonomic perspective: in every routine of archaeological work, it may provide a “diagnosis” -in terms of preservation conditions, resolution and integrity- for each record under study. It will help us understand and explain the complex genesis of current material patterns as well as recognizing the potential and limitations in the comparison of different samples at regional and supra-regional level (Borrazzo 2007: 147).

Taphonomic analyses are not usually applied in the field of historical archaeology, which is why we emphazise its inclusion within investigation protocols as a significant step towards the interpretation of historical archaeological sites and social practices of the past (Brittez 2009; Landon 2009; Weissel 2010; among others).

A TAPHONOMIC ITINERARY Taphonomy was originally defined by Efremov (1940) as the study of the changes that animal remains undergo from their death to their burial, focusing on their transition from the biosphere to the litosphere. Although taphonomic studies were developed in paleontological and archaeological studies by the end of the 19th century, it was not until the second half of the 20th century that they reached their present expression (Lyman 1994). Processual archaeology and actualistic studies had a strong influence on the development of taphonomic research in archaeology, which was exponential growth beginning in the late 1960s–early 1970s (Mengoni Goñalons 1988; Borrero 2011). Taphonomic studies in archaeological research have focused on evaluating the resolution of samples and understanding the dynamics generated by diverse agents on organic remains (Gifford González 1981; Lyman 1994, 2010). Thus, it considers the incidence of anthropic and natural agents on the formation of the archaeological record. In the last few years some researchers have gone beyond the original purview of taphonomic research, extending its theoretical-methodological precepts to the study of inorganic materials such as ceramics (Reid 1984; Ozán 2009; Fantuzzi 2010; Pérez Winter et al. 2010; Bernabeu Aubán et al. 2011), lithics (Hiscock 1985; Borrazzo 2004, 2007) and phytoliths (Piperno 1985). However, Lyman (2010), a staunch defender of “traditional taphonomy”, denies the inclusion of such approaches within the scope of taphonomic studies, believing them to be within the field of formation

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) processes (Lyman 2010). This conservative standpoint is untenable in the face of the new and numerous lines of inquiry that require expansion of analytical horizons to an “irrestrictive taphonomy” (Borrero 2011). That is why we prefer the following definition: Taphonomy today is much more than the study of the transition of organisms from the biosphere to the lithosphere; it is the study of the dynamic processes of modification of the original properties of all the components […] of any paleontological, archaeological or forensic assemblage, comprising its constituent materials and its context (Dominguez-Rodrigo et al. 2011: 5).

In this sense, we believe that the reconstruction of the taphonomic history of surface assemblages can provide information pertaining to aspects of sites that are often overlooked, especially in very large contexts and/or those where agricultural-livestock activities have been common.

ARCHAEOLOGICAL BACKGROUND

73

others). Here we mention a few interesting results to contextualize our study. Plowzone research has focused on horizontal shifting and fragmentation of the archaeological record caused by plowing (Roper 1976; Lewarch and O´Brien 1981a, 1981b; Ammerman 1985; Odell and Cowan 1987; González de Bonaveri and Senatore 1991; Dunnell and Simek 1995; Ots 2008; Harvey 2012, among others). There are two main views of the impact of agricultural work on archaeological sites. The first states that the plow destroys the original spatial association of surface artifacts and moves materials laterally up to 15 meters from their original location (Roper 1976; Odell and Cowan 1987). The second proposes that even if the plow is a significant agent in the fragmentation and shifting of archaeological remains, it does not completely destroy spatial associations, moving materials less than 6 meters from their initial position (Lewarch and O´Brien 1981a, 1981b; Riordan 1988; Yorston et al. 1990; Clark and Schofield 1991; Dunnell and Simek 1995). Therefore, interpretations of concentrations as the results of activity areas, dumps and/or subsurface dwellings should still be possible in the plowzone.

Plowzone archaeology

Supporters of both views agree that because materials are moved in the direction of the plow, single-direction plowing causes a bigger shift than bidirectional plowing, which tends to average the effect (Roper 1976; Odell and Cowan 1987). Another issue on which researchers generally agree derives from experiments that helped determine that the effect of plowing on fragmentation of archaeological remains is averaged through time—initially causing a rapid reduction in material size that is later stabilized— and that it generates a distribution tending towards unimodal (Lewarch and O’Brien 1981a, 1981b; Odell and Cowan 1987; Dunnell and Simek 1995; Boismier 1997). Results of numerous studies designed to understand relationships between artifact size and displacement have been inconsistent. That is, some show increased shifting among larger objects whereas in others indicate a random correlation between size/distance (Trubowitz 1978; Lewarch and O’Brien 1981a, 1981b; Dunnell 1990). Furthermore, Ammerman (1985) has indicated a need to consider the slope of the terrain, and he reports that shifting is greater on steep slopes.

The processes and effects on the archaeological r e c or d g e n e ra te d b y a g ric u ltu ra l t as ks has been addressed in numerous studies based on experimentation, simulation and interpretation of surface and subsurface records (Roper 1976; Lewarch and O´Brien 1981a, 1981b; Ammerman 1985; Odell and Cowan 1987; Yorston et al. 1990; González de Bonaveri and Senatore 1991; Dunnell and Simek 1995; Nicholson and Malainey 1995; Gómez Romero 1999; Niknami 2003; Ots 2008; Harvey 2012, among

The effect of plowing on vertical movement has been studied thoroughly by Dunnel and Simek (1995), who suggest that the area most substantially affected by plowing ranges between 20 and 40 cm below ground surface. The equipment used and geomorphological features are significant factors conditioning the effect on vertical displacement of the archaeological record. In affected areas, archaeologists should expect removal, mixture, and fragmentation of smaller objects located on the upper portion of the plowzone, whereas below

Over the last 30 years, numerous lines of research have been developed to analyze taphonomic evidence in the archaeological record, including the impact of plowing and trampling, and studies of alterations to inorganic materials such as pottery and glass. These studies are considered essential contributions to frames of reference that improve our taphonomic understanding of sites and archaeological assemblages at different scales. What follows is a brief introduction to research of significance to the present study. Although the cited works do not refer specifically to the same region or to similar environmental conditions, it is necessary to take them into account to assess the relevance of diverse processes, agents and effects in different contexts so that they contribute to our particular case study. The literature describing taphonomic research related to organic remains is vast and will not be considered in detail here (Binford 1981; Mengoni Goñalons 1988; Lyman 1994, among others).

74

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

this area, bigger objects, unaffected by this agent, should be found (Yorston et al 1990; Boismier 1997; Diez Martin 2009). As with horizontal shifting, the effect would be averaged through time (Lewarch and O´Brien 1981a, 1981b; Boismier 1997). This brief review summarizes some of the primary archaeological research on cultivated lands. Even when our results are not consistent with these findings, we will be able to establish a minimum/maximum effect of the impact of agricultural tasks in a site. We see an immediate need for experiments that take into account the particular characteristics of the study region (geomorphological features, rainfall patterns, type of crops, etc.) and their effects at particular stages in the agricultural cycle.

Trampling Studies Trampling is another area of research useful in assessing the effects of anthropic and non-anthropic agents in the vertical and horizontal movement of archaeological remains, and in the damage they produce on artifacts. Trampling by humans, animals (large and small), and agricultural equipment has been evaluated by numerous researchers. Experiments designed to assess the effects of different types of trampling on different artifact types in terms of both damage and horizontal and vertical displacement (Gifford González et al. 1985; Olsen and Shipman 1988; Mc Brearty et al. 1998; Flegenheimer and Weitzel 2007; Lopinot and Ray 2007; Eren et al. 2010, among others). Research on the effects of human trampling on a diversity of materials including some historic and industrially manufactured ones (e.g., ceramic, brick and handicraft pottery), are relevant to our study of the Mariano Miró assemblage (GiffordGonzález et al. 1985; Nielsen 1991). The type and compaction of sediments on which trampling took place are important variables given that penetrability diminish with increased substrate hardness (Nielsen 1991); all such studies confirm that when artifacts cannot penetrate the substrate, more damage results (Nielsen 1991; Flegenheimer and Weitzel 2007), whereas a soft substrate mitigates the effect and permits migration within the substrate (Gifford González et al. 1985). We will not devote attention to vertical artifact movement since this work focuses on surface assemblages. Horizontal shifting due to trampling creates a clustered pattern towards the margins of the affected area, which may resemble a discrete concentration such as those associated with activity areas or dumps (Nielsen 1991). Concentrations have size patterns characterized by an absence of small objects, which are incorporated into the sediment, while medium and large artifacts move the most and are likely to

be kicked (Nielsen 1991; Eren et al. 2010). Results obtained from experimentation indicate a problem of equifinality between the effects of plowing and trampling, which must be considered when interpreting archaeological records.

Studies of non-organic materials Materials found at Mariano Miró are typical of late 19th – early 20th century industrial production and may not be directly comparable those used in actualistic studies; ideally, studies should be replicated using materials that match the particilar characteristics of the Mariano Miró collections. Alteration to ceramics are conditioned by its porosity, hardness and composition (Skibo 1992; Ozán 2009; Fantuzzi 2010). The pottery recovered at Mariano Miró was mass-produced and characterized by low porosity, a lack of inclusions and high hardness due to high firing temperatures (e.g., earthenware, pottery, and porcelain, among others). Its properties are similar to those of glass, which is more resistant to chemical alterations, but more susceptible to mechanical damage because of their extreme fragility (Fantuzzi 2010). Due to their physical and chemical characteristics, glass is significantly affected by several agents. Surface alterations to glass artifacts have been characterized according to categories suggested by Pineau (2010): - Iridescence: presence of gleaming caused by sandy sediments and heat. - Chemical weathering (intemperizado): loss of original gleam caused by environmental conditions with no alteration of glass edges. - Physical weathering (erosionado): opacity of fragments and grinding of borders and walls caused by abrasive action including rolling down slopes or contact with water and/or sand. 

Alteration of metal artifacts cannot be assessed using the same analytical criteria since processes such as corrosion often preclude macroscopic observation of specimen surfaces. Although the contexts of the studies presented above differ from that of the present study, reviewing the taphonomic literature contextualizes our study of the surface record at Mariano Miró and helps us avoid issues of equifinality.

MARIANO MIRÓ SITE: HISTORICAL CONTEXT AND EARLY RESEARCH Mariano Miró is located in La Pampa Province (Chapaleufú Department; 35° 01´ 31.1´´ S, 63° 48´71.1´´ W), on dune-like plains formed by aeolian deposition of sand during the Pleistocene (Figure 1). The expansion agricultural has significantly modified the landscape, destroying the dunes and caldén (Prosopis caldenia) forests that once predominated in this region.

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina)

75

of success; as Jackson notes (1963 in Peyton 2012: 307) “Men have a tendency to forget rather than record disappointment and failure, so the story of the average camp has not won much space in old men’s memoirs”. This lack of documentation makes studies of oral history all the more important. Accounts from settlers of Hilario Lagos indicate that those who left Mariano Miró brought along tin plates, wood and every usable material to assemble their new Figure 1. Location of the site Mariano Miró in the north of the province of La Pampa, Argentina. dwellings (Apuntes para una nostalgia, 1985). Village abandonment was The few remaining dune formations in the area have forced by the abusive and speculative policies of big become fixed by vegetation, whereas disturbed fields landowners on which the lease system was based in have formed mollisols, making the region suitable for Pampean territory, as well as the fact that lands were agriculture and animal husbandry. Studies of soil pH often sublet by colonizing companies (Cazenave 1971; indicate slight acidity (pH 5.2 to 6.2) (Romano and Colombato 1995; Moroni 2007). Zinda 2007; Sainz Rosas et al. 2008). The region is considered humid, with an annual average rainfall of Presently, the place where the settlement was located 800 mm, falling predominantly between October and is plowzone largely under soybean cultivation (Figure March (Servicio Meteorológico Nacional). 2). For operative and visibility reasons archaeological fieldwork is performed after the harvest. Nonetheless, The village of Mariano Miró was founded in 1901, different crops (e.g., corn, soybean) leave diverse adjacent to an eponymous railway station. According visibility conditions in the field after the harvest. It is to data in the 1905 national Census of Territories, likely that these fields have been used for agriculture the village consisted of almost 500 inhabitants and and pasturage since the village was abandoned, a typical variety of stores related to agriculture and which has significant implications for modificaiton of livestock. It is believed that the main part of the village the archaeological record and its context. In 2011, a was extended 3 ha south of railway station, although local school teacher, Alicia Macagno, and her students some occupation to the north is mentioned as well from Rural School No. 65 collected surface materials (Apuntes para una nostalgia, 1985; Giorgio 2008). from the old settlement as an initiative to rediscover The land where the town grew up was leased to the Santa Marina family. Around 1911, after the lease contract was cancelled, the village was abandoned and its inhabitants founded new villages in the region including Alta Italia and Aguas Buenas (presently Hilario Lagos). The abandonment of Mariano Miró was gradual, as shown by the census of 1912, which indicates 254 inhabitants and continued use of the railway station (National Institute of Statistics and Census; Archive of the Railway Friends Association). Documentation of Mariano Miró’s decade of occupation is scarce, perhaps due to its very lack Figure 2. The Mariano Miró site covered by soybean cultivation in January of 2012

76

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

their past. They also excavated and removed a lot of material from a sector that we have geo-referenced and recorded on planimetries as Mmirop1 2. At the 2011 Provincial Science Fair, Ms. Macagno’s class presented their archaeological findings in the context of historical information pertaining to the abandoned village, after which the Cultural Research Department (Subsecretaría de Cultura de la Provincia de La Pampa) contacted our research team –directed by Alicia H. Tapia– to evaluate the archaeological site and recover the village heritage. In April of 2011 the first contact was made with the school community of Mariano Miró and in August fieldwork began to determine the site’s boundaries based on the distribution of surface materials. A 39,200 m 2 area south of the railway station was thus deemed the most likely area of occupation and targeted for the first topographic survey. In 2012, a systematic survey of the site was completed. The crew surveyed fourteen transects, oriented west to east and each divided into seven 40-meter segments labled A through G (Figure 3). Pedestrian survey was made with included use of a metal detector (Garret 1500 model) to identify concentrations of subsurface metals. Metal concentrations (N = 402) were found and subsequently mapped in two dimensions. Surface collection was performed by four surveyors walking in straight, parallel lines with a 2.5 -meter interval between them. Additionally, a 5 m2 grid and a 4 m2 trench were excavated. Complementary to the fieldwork, the research team actively engaged with the community to communicate the results of archaeological research, to reinforce

the importance of historic preservation and value of cultural heritage, and to increase local knowledge of the area’s history; allowing them to the conservation of the local archaeological heritage (Pineau et al. 2013).

METHODOLOGY M a r ia n o M ir ó ’ s t a p h o n o m i c h is t o r y wa s reconstructed through multi-scale (e.g., artifact, site) analysis of multiple variables (Behrensmeyer 1991) including: (artifact) weathering, trampling, thermal alteration, size distributions in surface collections; (site) topography, geomorphology, and the effects of plowing burrowing animals. Topography was studied during the 2012 field season and augmented with NASA’s high-resolution images (30 meters per pixel), to create a topographic model. Caves of burrowing animals were mapped because their creation can cause movement, accumulation and/or dispersal of archaeological materials (Wood and Johnson 1978; Politis and Madrid 1988; Mello Araujo and Marcelino 2003; Frontini 2011; Frontini and Ecosteguy 2011; Salemme et al. 2012, among others). Archaeological materials were sorted into three size classes: small (0.1 to 2 cm), medium (2.1 to 4 cm) and large (4.1 cm and over). The presence/absence of weathering, thermal alteration, trampling and plow marks was recorded. Weathering on vitreous fragments included both physical and chemical weathering (Sanford 1975; Purdy and Clark 1987; Pineau 2010). Weathering recording for ceramics followed criteria

Figure 3. Map of the systematic survey of the site across 14 transects of 280 metres each.

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) similar to those for glass, since ceramics often have glazed surfaces. On bone, weathering was identified following Behrensmeyer (1978). In all cases, all modifications on all sides of each artifact were recorded (Lyman 1994; Ozán 2009). Effects of thermal alteration are not uniform across material types. For bones, we used the color scales suggested by Shipman and coauthors (1984). Thermal alterations to pottery were identified by black surfaces and/or nuclei (Buenger 2003). On glass, several featuers were considered indications of thermal alteration, including iridescent or crackled surfaces, or deformation (Pineau 2010). Agricultural activities can have direct and indirect effects on the archaeological record. Direct impact includes plow marks on archaeological materials, such as scratches or fresh cracks. Indirect impact can be inferred from objects’ sizes and spatial distributions. Maps of objects’ spatial distributions and sizes can be overlain with satellite images that show plow turning marks to help determine whether plowing accumulated or shifted the materials. To understand the effects of trampling, we considered material size and displacement. However, multiple taphonomic agents cause similar correlations between the two variables. Thus, human, animal or equipment trampling may generate patterns that are easily confused with the shifting and fragmentation caused by plowing (Gifford-González et al. 1985; Nielsen 1991; Eren et al. 2010). Given the complexity of the relationships between multiple variables, we used bidimensional modeling aided by geographic information systems (GIS; ARCGIS10 software and ArcMap complement). This software calculates the nearest points to each raster cell using the kernel density method and Gauss Kruger cartographic projection band 4. We consulted documents, blueprints and photographs of Mariano Miró available in the Land Registry of Municipalidad (City Hall) de Santa Rosa, La Pampa; the Provincial Historical Archives (Santa Rosa, La Pampa); the Railway Friends Association; the Railway Museum “Scalabrini Ortiz;” the National Institute of Statistics and Census (INDEC); and the General Archive of the Nation (AGN). We believe that documentary sources and archaeological objects, as the material products of multiple social actors, are means to approach past representations and meanings in a comparative way (Gómez Romero and Pedrotta 1998; Carbonelli 2010; Pineau 2011). For this reason, we draw on both sources in the following analyses.

77

RESULTS Characteristics of the surface sample and its distribution We recovered 11,407 objects scattered across 32,900m2 of Mariano Miró’s surface. Materials were grouped by both raw material and functionality in the case of ceramics (pottery, porcelain, brick, tile, kaolin and earthenware). Also, for graphic display, we grouped uncommon materials (those with 30 or fewer specimens) into a “miscellaneous” category (plaster, tile, leather, sulphur, cement, wood, lithic, masonry, slate, kaolin and mortar). The sample contains a wide variety of materials, however glass (N = 8,324) and pottery (N = 1,125) predominate (Figure 4). Materials are predominantly medium-sized (55%) or small (46%), and though some large-size objects were found (9%). There is no clear relationship between artifacts’ size and their topographic location. Based on their morphology, marks/backstamps and manufacturing techniques, most of the artifacts could be assigned to the late 19th or early 20th century. While some of the materials may be younger materials may be present, these would not make up a significant proportion of the assemblage. There are concentrations of artifacts in the northwestern portion of the survey area, and lower frequencies in the southeast (Figure 5). That is, although materials are distributed across the site’s surface, they cluster in several high-density patches. One of these concentrations is located in the northwest corner (section A, transects 1, 2 and 3). On elevated portions of sections B and C, two smaller concentrations were observed. A fourth concentration exhibiting low material density was detected at section E in transects 7, 8 and 9, close to the point Mmirop1. These four higher-density patches are composed of small- and medium-sized materials, whereas large fragments are notebly concentrated in sections B and C of transects 3, 4 and 5. Glass predominates in all concentrations. Material-specific concentrations were also observed for metal (section B, transects 3, 4 and 5; section E, transects 8 and 9), earthenware (section E - transects 5, 6 and 7), brick (section C, transects 1, 2 and 3),

Figure 4. Amount of materials per category according to raw material.

78

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

Figure 5. Distribution of surface materials with georeferenced tracing of the village’s outline as indicated by documentary sources.

bone (section C, transects 3, 4 and 5), mineral coal (sections A and E, transects 1, 2 and 3), and pottery (section A, transects 1 and 2). The map of subsurface metal concentrations is consistent with surface artifact distributions (Figure 6). Furthermore, subsurface metal concentrations coincide with metal concentrations on the surface.

Alterations on materials The analysis of surface materials shows that 1,397 (12.7%NR3) exhibit evidence of weathering. Of the weathered materials, 92% is glass and the remaining 8% is composed of bone and pottery; 66.6% of weathered artifacts are affected on a single side. The distribution of weathered artifacts is homogeneous across the first seven transects, with the exception of two concentrations in sections B and E, which

coincide with a slope and plateau, respectively. Of the weathered artifacts, 33.4% showed signs of chemical weathering on both sides. Most of these were located in transect 2, sections A, C and E, which suggests they may have rolled down slopes in those sections. Weathering on glass and pottery was present as surface opacity, perhaps due to the relative acidity of the soil, which tends to promote chemical weathering these materials (Sandford 1975). Signs of mechanical weathering (erosion or corrasion) were not observed, despite the sandy substrate. Evidence of thermal alteration was observed on 164 artifacts (1.5% NR) recovered from artifact concentrations in transects 3, 4 and 9. Glass represents 79% of the thermally-altered sample, pottery 9% and bone 8% (Figure 7).

Figure 6. Density distribution of subsurface metal concentrations.

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina)

79

use of different plowing equipment including chisels, coulters and discs through the 1990s (INDEC). Since 2000, landowners have practiced no-till farming, which causes little alteration relative to plowing, although heavy equipment can still affect the archaeological record (INDEC; Héctor Morales pers. comm. 2012).

As mentioned, the abandonment of the Mariano Miró circa 1911 was a gradual process. During this process, the village’s 500 inhabitants surely generated a differential discard pattern, with normal, daily refuse being augmented by discard associated with moving, which would show a high fragmentation rate (Peyton 2012). Thus, on the one hand, we found a diversity of material fragments representative of daily life in Mariano Miró, such as glass containers (bottles, perfume and pharmacy jars), earthenware bottles, several types of pottery and porcelain, fragments of a porcelain doll, bone remains and parts of metal utensils. On the other hand, we found remains related to the buildings, such as brick, tile, nails and wooden fragments, among other things. In this sense, it is virtually impossible to distinguish daily life in the village from village abandonment based on surface artifacts or their distributions. Abandonment of the village—a product of landowners’ zeal for increased production— led to the demolition of structures after all reusable materials had been taken away (Figure 5). Ultimately, this resulted in a low-resolution archaeological record, making it difficult to differentiate based on surface remains events that occurred prior to abandonment from those that followed it.

Surface material distributions are affected by a variety of agents such as plowing, trampling, slope and gravity, and rainfall. To understand the specific effects of each agent on the archaeological record and to interpret our assemblage, we must consider the results of other studies. At the artifact level, such comparisons facilitated assessment of artifact size distributions, in this case dominated by medium/small artifacts and a low percentage of large objects (9%). Artifact size at Mariano Miró is unimodal, possibly as a result of fragmentation generated by plowing (Lewarch and O’Brien 1981a, 1981b; Odell and Cowan 1987; Dunell and Simek 1995; Boismier 1997). Furthermore, trampling on a sandy substrate is expected to bury smaller objects within the uppermost centimeters of the deposit while larger objects would remain on the surface (Baker 1978; Gifford González et al. 1985). However, this is not the pattern observed at our site. Nonetheless, we think plowing was not the primary agent responsible for material fragmentation since the type of sediment diminishes the possibility of artifact fragmentation; once artifacts are buried they do not encounter resistance as they would in a compact soil (Gifford González et al. 1985; Nielsen 1991). Although trampling may have had an influence on lateral displacement, particularly among larger artifacts that are prone to being kicked or dragged (Gifford González et al. 1985), it was not sufficient to create the expected size pattern at the site. Also, rainfall in addition to slope, may have moved some materials both downslope and laterally. Considering the heavy rainfalls at certain times of year, surface water may re-expose archaeological materials, though there is no evidence that this affected different sized materials differentially. The correlation between topography, rainfall and trampling, and the size of artifacts and their dispersal is not significant. Therefore, we suggest that, while they may have had some influence, the general patterns observed in the assemblage are likely the result of successive plowing that fragmented and dispersed artifacts over a wide surface (Yorston et al. 1990).

Analysis and evaluation of taphonomic processes involved in the formation of the site over the course of a century offer a means of understanding the natural processes and—in a future research—the social practices that influenced site formation. The Mariano Miró site has been impacted by agricultural and livestock activities. Agricultural censuses in the study region from 1937 to 2008 reveal simultaneous

At the site level, we were able to determine that the distribution of remains are consistent with the locations of buildings indicated on village maps from 1902, produced by Ferrocarril Central Oeste (Archives of the Railway Museum “Scalabrini Ortiz”) (Figure 5). Conversely, overlaying a map of burrowing animals caves (N = 80) on that of the spatial distribution of artifacts does not reveal a correlation. The material

Figure 7. Thermal alteration percentage of those materials found on the surface.

Direct plow marks were recorded on very few objects (N = 51; 0.5%), particularly small- and mediumsized glass pieces. However, thorough evaluation of the effects of plowing requires consideration fragmentation and horizontal dispersion.

DISCUSSION

80

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

concentration in the northwest sector of the site could primarily be the result of plows turning around in that section, according to our interpretations of agricultural equipment tracks observed in satellite images provided by Google Earth and ESRI’s server. Moreover, the slope in that sector could exacerbate artifact movement and accumulation initiated by plowing. Previous studies indicate that plowhing should have high impact on altering archaeological context. Even though in low frequencies, clusters of certain artifact categories and thermally altered material at Mariano Miró are remarkable. The presence of thermally-altered materials in sectors with high artifact densities and concentrations of bones may support the hypothesis that these areas were trash dumps. There is a high proportion of thermally-altered materials among those collected by the school group in section Mmirop1, particularly the glass, pottery and wood. The frequency and pattern of artifacts with this alteration lead us to believe it was not caused by a natural fire or deliberate burning of the field to eliminate weeds (Whyte 1984; Bennett 1999; Coirini and Karlin 2011). It remains unclear, however, whether these concentrations correspond to structures or trash pits or are simply random, a question that requires stratigraphic data to fully resolve. Moreover, excavations are recommended more generally since all of the strategraphic agents considered here also influence vertical distributions of artifacts. Subsurface testing should be done in conjunction with the development of experiments designed to identify the taphonomic processes that influenced our study area in particular. In light of this, we reiterate the benefits of studying taphonomic processes at every archaeological site and taking both surface and stratified deposits under consideration (Lewarch and O’Brien 1981a, 1981b; Dunnell and Dancey 1983; Butzer 1989; Dunnell 1992).

CONCLUSIONS Mariano Miró is an exceptional archaeological case: a village established by the railway that then succumbed to the advance of the agricultural frontier and landowners’ speculative tendencies. Studies of ghost towns or the archaeology of abandonment typically deal with abandoned villages where at least some structures still stand, such as Newhouse, Frisco and Silver Reef (Utah, USA) or sites associated with mining activities in Australia, New Zealand or Chile (Neville and Hooker 1997; Bell 1998; Vilches et al. 2008; Fuentes 2010; Lawrence and Davies 2010). Only the New Philadelphia site (Illinois, USA) is similar to our case study, having been abandoned gradually circa 1869 and later razed to permit agriculture. None of these cases have been considered from taphonomic perspective, however, and their archaeological records

were described as “intact,” leaving aside descriptions of particular alterations (e.g., roads, agriculture; Hargrave 2010). Despite differences in abandonment processes, material cultures, degree of preservation and approaches to their study, these sites share narratives about unsuccessful experiences that left traces on the landscape, memories and identities of the descendants of those upon whom an exodus was forced. Historic archaeology will help us understand the histories of those settlers in the region, and aid preservation of their material and immaterial heritage. Consideration of diverse variables and scales of analysis allowed us to describe a complex process in which multiple agents acted over the course of the last century. We acknowledge that there are issues of equifinality when attempting to distinguish the effects of some agents. Nevertheless, we propose that plowing was the most significant taphonomic agent at Mariano Miró, fragmenting and moving artifacts. However, some of our observations suggest that plowing did not completely obliterate patterns generated during occupation and abandonment of the village. For example, the three largest artifact concentrations in section A of transects 1, 2 and 3; sections B and C of transects 3, 4 and 5; and section E of transects 7, 8 and 9 correspond to structures or loci, such as dumps used during the town’s occupation or abandonment. These high-density patches consist of small- and mediumsized materials, whereas large fragments are primarily concentrated in sections B and C of transects 3, 4 and 5, where there are also numerous thermally-altered materials and bones. This also supports the idea that plowing disturbance was not sufficient to completely alter artifact clustering, though we are well aware that we do not yet have enough information to confirm this hypothesis. Toward this end, we will complete additional systematic surveys in the light of the data collected here. Stratigraphic information will improve our knowledge of the effects of taphonomic agents on artifacts’ vertical displacement. Moreover, it is vital that we design experiments to helps us to understand the effects of agents involved in the formation and alteration of the material record in the study region. Finally, given the site’s size and the possibility that some structures remain, we intend to conduct geophysical survey as well. We believe that the surface record, despite its limitations, provides valuable information and can be used to understand both formation processes and social practices at a site (Butzer 1989; Dunnell 1992). A taphonomic perspective allows us to pose new questions and generate new expectations for interpreting the site. The study presented here highlights the importance of a taphonomic perspective for interpreting a site where all that is left of a community of 500 inhabitant are numerous fragments found on the surface.

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) Acknowledgements We thank Mr. Jorge Alsina and Héctor Morales for their generous hospitality, and the communities of Hilario Lagos and Rural School No. 65 in Mariano Miró, particularly Alicia Macagno.

REFERENCES Apuntes para una nostalgia 1985 La Pampa, Producción gráfica N. D. F. & asociados consultora para el desarrollo de la comunidad visual, La Pampa. Ammerman, A. J. 1985 Plow-zone experiments in Calabria, Italy. Journal of Field Archaeology 12: 33-40. Baker, C. M. 1978 The size effect: An explanation of variability in surface artifact assemblage content. American Antiquity 43: 288-293. Behrensmeyer, A. 1978 Taphonomic and Ecologic Information from Bone Weathering. Paleobiology 4 (2): 150-162. 1991 Terrestrial Vertebrate Accumulations. In Taphonomy: Releasing the Data Locked in the Fossil Record, edited by P. Allison y D. E. G. Briggs, 291335. Plenum Press, New York. Bell, P. 1998 The fabric and structure of Australian mining settlements. In Social Approaches to an Industrial Past: The Archaeology and Anthropology of Mining, edited by B. Knapp, V. Piggott, and E. Herbert, pp 25-38. Routledge, London. Bennett, J. 1999 Thermal alteration of buried bone. Journal of Archaeological Science 26: 33-40. Bernabeu Aubán J., P. García Borja, O. Gómez Pérez and L. Molina Balaguer 2011 Las primeras producciones cerámicas. El VI milenio CAL AC en la península ibérica. Saguntum. Papeles del Laboratorio de Arqueología de Valencia 12: 17-33. Binford, L. 1981 Bones: Ancient Men and Modern Myths. Academic Press, New York. Boismier, W. A. 1997 Modelling the effects of tillage processes on artefact distributions in the ploughsoil. A simulation study of tillage-induced pattern formation. BAR British Series 259. Archaeopress, Oxford. Borrazzo, K. 2004 Hacia una tafonomía lítica: el análisis tafonómico y tecnológico de los conjuntos artefactuales líticos de

81

superficie provenientes de los loci San Genaro 3 y 4 (Bahía San Sebastián - Tierra del Fuego, Argentina). Undergraduate Thesis, Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2007 Aporte de la tafonomía lítica al estudio de distribuciones artefactuales en ambientes lacustres: el caso del sistema lacustre al sur del Lago Argentino (Santa Cruz, Argentina). Comechingonia Virtual 3: 132-153. Borrero, L. 2011 La función transdisciplinaria de la arqueozoología en el siglo XXI: restos animales y más allá. Antípoda, Revista de Antropología y Arqueología 13: 267-274. Brittez, F. 2009 Zooarqueología, tafonomía y procesos de formación de sitios rurales pampeanos: estado de la cuestión y expectativas para momentos tardíos. Revista de Arqueología Histórica Argentina y Latinoamericana 3: 47-68. Buenger, B. 2003 The impact of wildland and prescribed fire on archaeological resources. PhD Dissertation. University of Kansas, Kansas. Butzer, K. 1989 Arqueología. Una ecología del hombre. Bellaterra, Barcelona. Carbonelli, J. P. 2010 La fuente escrita, espacio de confrontación. La Zaranda de Ideas. Revista de Jóvenes Investigadores en Arqueología 6: 9-23. Cazenave, W. 1971 El Ferrocarril en La Pampa. Dirección de Prensa del Gobierno de La Pampa, La Pampa. Clark, J. D. and A. J. Schofield 1991 By experiment and calibration: An integrated approach to archaeology of the ploughsoil. Interpreting artefact scatters. In Contribution to plowzone archaeology, edited by A. J. Schofield, pp. 93-105. Oxbow, Oxford. Coirini, R. and M. Karlin 2011 Modelos de Producción Sostenible para la Ecorregión Espinal Informe técnico en el marco de la consultoría: Manual de Buenas Prácticas y Modelos de Producción Sostenible. Freiburg, Unique. Colombato, J. 1995 Trillar era una Fiesta. Poblamiento y puesta en producción de La Pampa territoriana. Facultad de Ciencias Humanas, Universidad Nacional de La Pampa, Santa Rosa. Diez Martín, F. 2009 Ploughzone archaeology. Some remarks. BSAA Arqueología LXXV: 23-40.

82

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

Domínguez-Rodrigo, M., S. Fernández-López and L. Alcalá 2011 How can taphonomy be defined in the XXI Century? Journal of Taphonomy 9: 1-13. Dunnell, R. C. 1990 Artifact size and lateral displacement under tillage: Comments on the Odell and Cowan experiment. American Antiquity 55: 592-594. 1992 The notion Site. In Space, time, and archeological landscape, edited by J. Rossignol and L. Wandsnider, pp. 16-41. Plenum Press, New York. Dunnell, R. and W. Dancey 1983 The Siteless Survey: A Regional Scale Data Collection Strategy. In Advances in Archaeological Method and Theory 6, edited by M. Schiffer. pp. 267287. Academic Press, New York. Dunnell, R. C. and J. Simek 1995 Artifact size and plowzone processes. Journal of Field Archaeology 22: 305-319. Efremov, I. 1940 Taphonomy: a new branch of paleontology. Pan Amercian Geologist 74: 81-93. Eren, M. I., A. Durant, C. Neudorf, M. Haslam, C. Shipton, J. Bora, R. Korisettar, R. and M. Petraglia 2010 Experimental examination of animal trampling effects on artifact movement in dry and water saturated substrates: a test case from South India. Journal of Archaeological Science 37: 3010-3021.

Archeological Method and Theory 4, edited by M. Schiffer, pp. 365-438. Academic Press, New York. Gifford-González, D., D. B. Damrosch, D. R. Damrosch, J. Pryor and Robert L. Thunen 1985 Third Dimension in Site Structure: An Experiment in Trampling and Vertical Dispersal. American Antiquity 50 (4): 803-818. Giorgio, N. 2008 1900-2008. Resumen de una historia olvidada. Auge y Ocaso de un Asentamiento Poblacional. Hilario Lagos, La Pampa. Gómez Romero, F. 1999 Sobre lo arado el pasado: arqueología histórica en los alrededores del Fortín Miñana (1860-1869). Biblos, Buenos Aires. Gómez Romero, F. and V. Pedrotta 1998 Historical Archeology: an outlook from Argentinean Pampas. International Journal of Historical Archeology 2 (2): 113-131. González de Bonaveri I. and X. Senatore 1991 Procesos de formación en el sitio San Ramón 4. Boletín del Centro 2: 65-77. Hargrave, M. 2010 Geophysical Detections of Features and Community Plan at New Philadelphia, Illinois. Historical Archaeology 44 (1): 43-57.

Fantuzzi, L. 2010 La alteración posdeposicional del material cerámico. Agentes, procesos y consecuencias para su preservación e interpretación arqueológica. Comechingonia Virtual 4 (1): 27-59.

Harvey, K. G. 2012 Who Needs a Plow-Zone? Using a Common Site Mapping Method in a New Way At the Silvernale Site (21GD03). Thesis for Master of Science. Department of Anthropology, Minnesota State University, Mankato Mankato.

Flegenheimer, N. y C. Weitzel 2007 Caminar sobre piedras: los artefactos fracturados de Cerro El Sombrero. XVI Congreso Nacional de Arqueología Argentina, t. III: 263-267. Universidad Nacional de Jujuy, San Salvador de Jujuy.

Hiscock, P. 1985 The need for a taphonomic perspective in stone artefact analysis, Queensland Archaeological Research 2: 82-95.

Frontini, R. 2011 El aprovechamiento de animales en valles fluviales y lagunas del sur bonaerense durante el Holoceno. Unpublished PhD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires.

Landon, D. 2009 An Update on Zooarchaeology and Historical Archaeology: Progress and Prospects. In International Handbook of Historical Archaeology, edited by T. Majewski and D. Gaimster, pp. 77-104. Springer, New York.

Frontini, R. and P. Ecosteguy 2011 Chaetophractus villosus: A Disturbing Agent for Archaeological Contexts. International Journal of Osteoarchaeology 22 (5): 603-615.

Lawrence, S. and P. Davies 2010 An Archaeology of Australia since 1788. Springer, New York.

Fuentes, M. 2010 Headline for an Archaeology of capitalism in Chile (1880-1930). Entelequia. Revista Interdisciplinar 11: 173-195.

Lewarch, D. and M. J. O’Brien 1981a The expanding role of surface assemblages in archaeological research. In Advances in Archaeological Method and Theory, edited by M. Schiffer, pp. 297342. Academic Press, New York.

Gifford-Gonzalez, D. 1981 Taphonomy and paleocology: A critical review of Archeology´s sister disciplines. In Advances in

Taphonomy of a village: the early 20th century site of Mariano Miró (Chapaleufú department, La Pampa, Argentina) Lewarch, D. and M. J. O’Brien (editors) 1981b Effect of short term tillage on aggregate provenience surface pattern. In Plowzone archaeology: contributions to theory and technique, pp. 7-49. Vanderbilt University Publications in Anthropology, Nashville. Lopinot, N. and J. Ray 2007 Trampling Experiments in the Search for the Earliest Americans. American Antiquity 72 (4): 771-782. Lyman, R. 1994 Vertebrate taphonomy. Cambridge University Press, Cambridge. 2010 What Taphonomy Is, What it Isn’t, and Why Taphonomists Should Care about the Difference. Journal of Taphonomy 8 (1): 1-16. Mc Brearty, S., L. Bishop, T. Plummer, R. Dewar and N. Conard 1998 Tools underfoot: human trampling as an agent of lithic artifact edge modification. American Antiquity 63 (1): 108-122. Mello Araujo, A. and J. C. Marcelino 2003 The Role of Armadillos in the Movement of Archaeological Materials: An Experimental Approach. Geoarchaeology: An International Journal 18 (4): 433-460. Mengoni Goñalons, G. 1988 Análisis de los materiales faunísticos de sitios arqueológicos. Xama 1: 71-120. Moroni, M. 2007 La nacionalización de la frontera pampeana y la formación del Estado Argentino. Secuencia 67: 69-89. Neville, R. and R. Hooker 1997 An archaeologist guide to miniming terminology. Australasian Historical Archeology 15: 3-29. Nicholson, B. A. and M. Malainey 1995 Sub-Ploughzone Testing at the Lowton Site (DiLv-3): The Vickers Focus Type Site in Southwest Manitoba. Canadian Journal of Archaeology 19: 87-100. Nielsen, A. E. 1991 Trampling the Archaeological Record: an Experimental Study. American Antiquity 56: 483-503. Niknami, K. A. 2003 A stochastic model to simulate and predict Archaeological landscape taphonomy: monitoring cultural landscape values based on an Iranian survey project. Archeologia e Calcolatori 18: 101-120. Odell, G. H. and F. Cowan 1987 Estimating tillage effects on artifact distributions. American Antiquity 52: 456-484. Olsen, S. and P. Shipman 1988 Surface modification on bone: trampling versus butchery. Journal of Archaeological Science 15: 535-553.

83

Oszlak, O. 1997 La formación del Estado argentino. Planeta, Buenos Aires. Ots, M. J. 2008 Study of disturbance induced by tillage on ceramic assemblages in Agua Amarga (Tupungato, Mendoza, Argentina). Chungara. Revista de Antropología Chilena 40 (2): 145-160. Ozán, I. 2009 Procesos de formación del registro cerámico en cazadores recolectores del centro-este y sudoeste de la Provincia de La Pampa. Undergraduate Thesis, Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. Pérez Winter, C., M. Fagundes and S.Rodrigues 2010 Una aproximación tafonómica al análisis arqueológico del material cerámico: caso experimental sitio São Lourenço 1, Municipio de Ituiutaba (MG). Revista UnG Geociências 9 (1): 14-33. Peyton, P. 2012 The Archeology of abandonment ghost town of the American west. PhD Dissertation. University of Leicester, Leicester. Pineau, V. 2010 Esto no es soplar y hacer botellas. Precisando la cronología de un sitio eanquel a partir de sus fragmentos vítreos. In De ranqueles, militares y religiosos en el mamül mapu. Enfoque arqueológico y etnohistórico, edited by A. Tapia. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. CD-ROM. 2011 Las bebidas alcohólicas en las relaciones entre aborígenes y militares. Análisis arqueológico en la Frontera del Sur Argentina-Siglo XVIII-XIX. Editorial Académica Española, España. Pineau, V., C. Landa, E. Montanari and J. Doval 2013 Experiencias de transferencia en Arqueología histórica del norte de La Pampa. Una reflexión desde la Arqueología pública. Work presented at XVIII Congreso Nacional de Arqueología Argentina. Universidad Nacional de La Rioja, Argentina. Piperno, D. 1985 Phytolith Taphonomy and Distributions in Archaeological Sediments from Panamá. Journal of Archaeological Science 12: 247-267. Politis, G. and P. Madrid 1988 Un hueso duro de roer: análisis preliminar de la tafonomía del sitio Laguna Tres Reyes 1 (Pdo. de Adolfo Gonzáles Chaves, Pcia. de Buenos Aires). In De Procesos, Contextos y Otros Huesos, edited by N. Ratto and A. Haber, pp. 29-44. Facultad de Filosofía y Letras, Buenos Aires.

84

C. Landa et al. - Intersecciones en Antropología - Special Issue 1 (2014) 71-84

Purdy, B. and D. Clark 1987 Weathering of inorganic materials: Dating and other applications. In Advances in Archaeological Method and Theory 11, edited by M. Schiffer, pp. 211253. Academic Press, New York. Reid, K. 1984 Fire and ice: New evidence for the production and preservation of Late Archaic fiber-tempered pottery in the middle-latitude lowlands. American Antiquity 49 (1): 55-76. Riordan, T. 1988 The Interpretation of Seventeenth Century Sites Through Plowzone Surface Collections: Examples from St. Mary’s City, Maryland. Historical Archaeology 22: 2-16. Romano, N. and R. Zinda 2007 Contenido de fósforo extractable, ph y materia orgánica en los suelos del este de la provincia de La Pampa. Informaciones Agronómicas 1: 1-6. Roper, D. C. 1976 Lateral displacement of artifacts due to plowing. American Antiquity 41: 372-374. Sainz Rosas, H, H. Echeverría and H. Angelini 2008 Niveles de materia orgánica y pH en suelos agrícolas de la región pampeana y extra pampeana argentina. Informes Agronómicos 2: 6-12. Salemme, M., P. Ecosteguy and R. Frontini 2012 La fauna de porte menor en sitios arqueológicos de la región pampeana, Argentina. Agente disturbador vs. recurso económico. Archaeofauna 21: 163-185. Sanford, E. 1975 Conservation of artifacts: a question of survival. Historical Archeology 9: 55-64. Shipman, P., G. Foster and M. Schoeninger 1984 Burnt bones and teeth. An experimental Study of color, morphology, crystal structure an shrinkage. Journal of Anthropological Science 11: 307-325. Skibo, J. M. 1992 Pottery Function. A use-alteration perspective. Plenum Press, New York.

Trubowitz, N. L. 1978 The persistence of settlement patterns in a cultivated field. In Essays in northeastern archaeology in memory of Marian E. White, edited by W. Englebrecht and D. K. Grayson, pp. 41-66. Occasional Publications in Northeastern Archaeology, Ringe. Vilches, F., C. Rees and C. Silva 2008 Archaeology of nitrate settlements in the Antofagasta region (1880-1930): Summary and perspectives. Chungara. Revista de Antropología chilena 40 (1): 19-30. Weissel, M. 2010 Los suelos de la Ciudad de Buenos Aires, una perspectiva arqueológica. Revista de Arqueología Histórica Argentina y Latinoamericana 4: 41-66. Whyte, T. 1984 Lithic artifact burning and archaeological deposit formation on three early archaic sites in east Tennessee. M. A. Thesis. University of Tennessee, Tennessee. Wood, W. and D. Johnson 1978 A survey of disturbance processes in archaeological site formation. In Advances in Archaeological Method and Theory 1, edited by M. Schiffer, pp. 315–381. Academic Press, New York. Yorston, R. M., V. L. Gaffney and P. J. Reynolds 1990 Simulation of artifact movement due to cultivation. Journal of Archaeological Science 17: 67-83.

NOTES 1.- In Argentinian historiography, the so-called “Conquest of the Desert” was set up as a series of military campaigns and actions carried out by the Argentinean Army against diverse indigenous people between the years 1878 and 1885 in the Pampean and Patagonian regions. Its outcome was the conquest of the territory and the control, reduction and genocide of the native inhabitants. 2.- An inventory of this collection registered 4,621 artifacts. 3.- The acronym NR is used to refer to the total Number of Remains. 4.- It would be difficult to identify the specific agent that caused trampling due to equifinality problems.

|

85

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) Catalina Balirán Received 18 September 2013. Accepted 20 April 2014

ABSTRACT This work assessess the impact of taphonomic processes on the surface lithic record of La Verdadera Argentina archaeological locality (Santa Cruz, Argentina). Different stages of weathering were observed on lithic artifacts´ surfaces, the edges consistently exhibiting less intense alteration, which may be the result of a reclamation process of the archaeological record or of animal trampling. At such, this project was designed to understand the potential effect of animal trampling on surface lithic artifacts. Toward this end, two experimental plots were established in La Verdadera Argentina. Results of these actualistic tests are used as a frame of reference for the taphonomic analysis of the surface artifact assemblage recovered along an archaeological survey transect (T9). Preliminary results indicate that the effects of taphonomic processes are registered very quickly. The hypothesis explaining the edge modifications observed in the local lithic record as a result of taphonomic processes cannot be discarded. Keywords: Lithic taphonomy; Lutite; Weathering; Archaeology; Patagonia.

RESUMEN PISOTEO, TAFONOMÍA Y EXPERIMENTOS CON ARTEFACTOS LÍTICOS EN EL SUDESTE DE LA SIERRA BAGUALES (SANTA CRUZ, ARGENTINA). Este trabajo tiene como objetivo general discutir la incidencia de los procesos tafonómicos que actúan sobre el registro lítico de superficie en la localidad arqueológica La Verdadera Argentina (Santa Cruz, Argentina). En la superficie de dichos artefactos se observan diferentes grados de meteorización, siendo siempre los filos los que exhiben menor intensidad de alteración. Se ha planteado que esta diferencia puede ser resultado tanto de prácticas de reclamación del registro arqueológico como producto del pisoteo de animales. Este trabajo busca evaluar los efectos potenciales del pisoteo sobre los artefactos líticos de superficie. Para ello se sembraron dos pistas experimentales en la localidad. La información actualística obtenida se utiliza como marco de referencia para el análisis tafonómico del conjunto artefactual de superficie recuperado en una transecta (T9). Los primeros resultados indican que los efectos derivados de los procesos tafonómicos son registrables en el corto plazo. Se concluye que la hipótesis que explica el fenómeno observado en el registro lítico como producto de procesos tafonómicos no puede ser descartada. Palabras clave: Tafonomía lítica; Lutita; Meteorización; Arqueología; Patagonia.

Catalina Balirán. Facultad de Filosofía y Letras, Universidad de Buenos Aires. Puán 480 (C1406CQJ), Ciudad Autónoma de Buenos Aires. Argentina. [email protected] Intersecciones en Antropología - Special Issue 1: 85-95. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

86

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95 INTRODUCTION

Understanding the role of taphonomic processes in the transformation of lithic archaeological records is key to their interpretation (Hiscock 1985; Schiffer 1987; Eren et al. 2010, among others). The effects of trampling have been studied extensively (Wilk and Schiffer 1979; Gifford-Gonzalez et al. 1985; Nielsen 1991; Lopinot and Ray 2007; Eren et al. 2010, among many others). This paper aims to contribute to taphonomic studies, focusing on animal trampling and its effect on surface lithic archaeological records. This work is part of a long-term, actualistic program of investigation geared towards understanding the effects of trampling on the lithic record at La Verdadera Argentia (LVA) locality (Argentine Patagonia).

BACKGROUND Trampling taphonomy The occurrence of artifacts produced or transformed by taphonomic processes is a topic that has been studied extensively (Hiscock 1985; Pryor 1988; Peacock 1991; Thiébaut et al. 2010b; Borrazzo 2011a). Different lines of investigation regarding features observed on these artifacts or pseudo-artifacts suggest how this kind of record is produced and how it should be studied. When artifacts are affected by geomorphological processes, attributes associated with weathering should indicate the gradual action of geomorphological processes in the form of differing degrees of surface alteration (Peacock 1991). Nonetheless, several authors advise the use of multiple attributes to assess the origin of surface characteristics (Peacock 1991; Burroni et al. 2002; Borrazzo 2011a). For some of these authors, comparison between a lithic assemblage and the region’s prehistoric technological baseline is key to detecting patterns. Such studies aim to understand how taphonomic processes alter artifacts and create pseudoartifacts that mimic those of anthropic origin. Much experimental work has been done to link characteristics of the archaeological record in general and in lithic artifacts in particular to specific causes (Gifford-Gonzalez et al. 1985; Burroni et al. 2002; Weitzel and Colombo 2006; Lopinot and Ray 2007; Borrazzo 2008, 2011a y b; Schoville and Brown 2010; Weitzel 2010, 2012; Eren et al. 2010, 2011; Pargeter 2011; Balirán 2012; Weitzel et al. 2014). Among them, trampling experiments provide a frame of reference for understanding artifact distributions (Gifford-Gonzalez et al. 1985; Pintar 1987; Nielsen 1991; Osborn and Hartley 1991; Eren et al. 2010; Borrazzo 2011b, among many others), and factors that alter artifacts or produce pseudo-artifacts (Gifford-Gonzalez et al. 1985; Burroni et al. 2002; Flegenheimer and Weitzel 2007;

Lopinot and Ray 2007; Schoville and Brown 2010; Weitzel 2010, 2012; Borrazzo 2011a; Eren et al. 2011; Pargeter 2011; Balirán 2012; Weitzel et al. 2014).

Study region La Verdadera Argentina archaeological locality is located in the southeast of the Baguales Range, Santa Cruz Province, Argentina. It is a steppic environment, between 300 to 600 m asl, characterized by a mean annual rainfall of 300 mm, and mean annual temperature of 8° C. Both native and exotic fauna are present today (Borrazzo 2011b), including (native) guanaco (Lama guanicoe), grey fox (Pseudalopex griseus), choique (Rhea pennata), and puma (Puma concolor puma); and (exotic) cattle and horses. La Verdadera Argentina ranch was established in 1923 (J. P. Riquez, personal communication, 2011), from which date forward the introduction of large numbers of European cattle significantly amplified the trampling effects of the local fauna that has been present throughout the Holocene. Several lithic sources have been recorded in the locality, occurring mainly as secondary deposits composed of several lithologies (chert, dacite, diabase, and lutite) available as boulders and/or large blocks. However, lutite is the most frequently occurring material in all LVA lithic assemblages (Borrazzo 2006, 2008; Borrero et al. 2006). The chronology for local human occupation was obtained from the stratified Cerro León 1 and 3 rock shelter sites. Humans appear to have been present in the area throughout the Holocene, between 8,856 ± 84 and 907 ± 45 14C years BP1 (Borrazzo 2006, 2008; Borrero et al. 2006; Borrero and Borrazzo 2011). The southeastern extent of Baguales Range has been characterized as marginal to the home ranges of populations settled to the east (Franco and Borrero 2000; Borrazzo 2006, 2008; Borrero et al. 2006). The absence of archaeological materials in viable local rock shelters (e.g., LVA cave; Borrazzo 2008) is consistent with this interpretation. Although the LVA archaeological locality has been occupied throughout the Holocene, the archaeological record is sparse. Open-air surface sites are the most common evidence of a human presence in the locality and these are primarily lithic scatters, probably indicating low sedimentation rates (Borrazzo 2011b). This paper addresses the formation of surface lithic assemblages in the LVA archaeological locality. Surface lithic assemblages collected from the LVA locality contain high frequencies of lutite tools weathered to differing degrees. Retouched and flaked edges exhibit lower intensities of weathering. In a previous publication, Balirán (2012) suggested that this

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) phenomenon could be explained by either reclamation -reintroduction of artifacts from the archaeological contexts to systemic contexts (Schiffer 1987)- or taphonomic processes, particularly animal trampling in the current context. This led to a pilot project aimed at evaluating the impact of trampling on surface lithic artifacts. The focus of this work is to quantify the occurrence of fractures and/or macroscopic edge damage in experimental samples and to compare these patterns to those observed during the taphonomic analysis of a local archaeological surface assemblage (T9) in order to evaluate the relevance of experimental data for interpreting the archaeological record.

Behavioral vs. taphonomic processes: working hypotheses As mentioned, LVA´s surface lithic assemblages are dominated by lutite artifacts. Weathering is readily identifiable on this raw material since the color of the rock surface becomes lighter as weathering increases. A recurring pattern of varying degrees of weathering (sensu Borrazzo 2006) among lithic artifacts was recorded; artifact edges—both isolated and continuous flake scars—are less weathered than other surfaces (Figure 1). These observations raise the question: Are the observed intra-artifact differences in weathering a result of human behavior or of taphonomic processes? To answer this question it is necessary to examine both possibilities and determine how each of these factors might have contributed to the formation of the archaeological record throughout the Holocene. Thus, the aim of this paper is to compare experimental trampling data and archaeological collections. Currently we know that while archaeological evidence at LVA is sparse, the locality was available to and

87

visited by hunter-gatherers during the Holocene and, although this pattern is interpreted from stratified sites, it is assumed that surface assemblages reflect a similar level of human use. One hypothesis to explain the observed patterns of weathering on lutite artifact surfaces is artifact reclamation (sensu Schiffer 1987). That is, if different degrees of weathering can be interpreted as different exposure times of rock surfaces, we can assume that a considerable amount of time passed between the production of an artifact and any other scar exhibiting a lesser amount of weathering. Therefore, lower weathering stages on edges would be the result of a provisioning strategy that seeks to save time and energy by resharpening abandoned tools or by selecting preexisting flakes as blanks for tool manufacture. An alternative hypothesis explains the occurrence of lessweathered fractures and/or flake scars as the effects of taphonomic processes. An assessment of local taphonomic agents and processes suggests that animal trampling is the most likely source of the pattern.

MATERIALS AND METHODS Several features of the LVA locality make this latter hypothesis plausible: a low sedimentation rate, which reduces the likelihood of artifact burial; a generally hard substrate with ample gravels and sparse vegetation cover; and an abundance of native wildlife and European livestock. In this context, it is reasonable to propose that the surface lithic record is subject to animal trampling and that this has been the case for a long time. To test this hypothesis, a long-term experimental study was specifically designed to assess how taphonomic processes act on the LVA surface lithic record. In this first stage of our research, we focus on the effects of the animal trampling.

Figure 1. Artifacts from archaeological sample T9 that exhibit different weathering stages on their surfaces. Lower stages can be observed on the edges.

88

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95

Transect 9 (T9) The archaeological material discussed in this paper comes from a surface collection identified as Transect 9 (T9). This transect runs NW-SE and the surface slopes gently to the east. Visibility ranges from 50% to 100% and two surveyors collected all surface materials within an area 250 m long by 10 m wide. The sample is composed of 305 artifacts, 87.87% (N = 268) of which are made from lutite. The remaining 12.13% (N = 37) were manufactured from other local and non-local raw materials (e.g., chert, basalt, dacite). This study considers only the lutite artifacts, since 1) this material exhibits higher degrees of macroscopic weathering as surface exposition time increases and 2) it is the most common raw material in T9 and other archaeological samples collected in the area. Previous work in the study area called attention to taphonomic processes affecting surface lithic assemblages and suggested the need to account for such processes during techno-morphologic analyses (Borrazzo 2006, 2008). Here, we follow Hiscock (1985), who posits that lithic artifacts change between their deposition and later retrieval and that, therefore, the study of formation processes is not only useful, but necessary for proper interpretation of the lithic record. We also follow Borrazzo’s (2004, 2006, 2010) approach to taphonomic analysis of archaeological lithic assemblages, defining the taphonomy of lithic artifacts as “an archaeological and actualistic study which describes, defines and systematizes the effects produced by natural and cultural processes and agents that acted on lithic artifact sets since their deposition and until their retrieval from the archaeological context” (Borrazzo 2004: 9). Chemical weathering intensity is the focus of this taphonomic analysis. Borrazzo (2004, 2006) defines four stages (0, 1, 2 and 3) of abrasion (physical weathering) on different parent materials, while Hiscock (1985) describes four continuous but different stages for chemical weathering in chert, ranging from “fresh” to “heavily weathered.” Following these two authors, a qualitative scale of lutite weathering is developed here; higher degrees of weathering result in a more porous rock texture and a lighter or whiter color: Stage 0: no weathering, or “fresh” in Hiscock’s (1985) terminology Stage 1: the rock surface exhibits a thin, light grey coating. The texture of the rock remains similar to that in stage 0. Stage 2: the surface turns lighter grey and becomes porous. Stage 3: the rock texture is rough and very porous and the surface has an almost white coloration.

Techno-morphological analysis of both experimental and archaeological samples was conducted following Aschero’s (1975, 1983) protocols. We recorded the occurrence of less-weathered fractures and micro-flaking on the edges of artifacts recovered from surface contexts. To build a framework for systematic analysis of the origin of these features, we designed a trampling experiment. The author established two experimental plots (see below) based on previous experimental work in the area (Borrazzo 2011b) as well as more general experimental research on formation processes (Schiffer 1987; Borrero 1991; Kligmann 2009) and trampling in particular (see Pryor 1988; McBrearty et al. 1998; Eren et al. 2010; Weitzel 2010; Thiébaut et al. 2010b). Trampling experiments aim to link particular effects with their potential causes; this information is then used to interpret the archaeological record (e.g., Nielsen 1991; Flegenheimer and Weitzel 2007; Eren et al. 2010; Weitzel 2010). In this particular case, special attention was paid to average thickness of fracture sections since it has been demonstrated that this attribute is a good indicator of flake breakage by trampling (Merenzon 1988; Borrazzo 2010; Weitzel 2010; Jennings 2011; Weitzel et al. 2014): the thinner the flake, the more likely it is to be broken during trampling (Borrazzo 2010). The proposed maximum thickness for trampling fractures is 7 mm (Flegenheimer and Weitzel 2007; Weitzel 2010, 2012; Weitzel et al. 2014).

Experimental plots In 2011, two plots were established in LVA. This longitudinal study includes annual survey for each of 10 years (the time it took another local experimental plot to stabilize; Borrazzo 2011b), or until no changes to the experimental assemblage are recorded during three consecutive surveys (i.e., the plot stabilizes), whichever occurs soonest. The experiment consisted of three stages: - sample preparation - plot set up - survey

The first stage included manufacture of a sample of lutite artifact replicas (N = 100) using a hard hammer and free hand percussion, the most frequent technique recorded in LVA lithic assemblages. Each piece was labeled, measured, and photographed, and a drawing of its outline was produced. This information was recorded to aid detection of any changes in the sample through time. Subsequently, each piece was painted with white diluted acrylic to increase the visibility of changes (fractures, flaking, micro-flaking) to dark gray lutite surfaces. Subsequently, the sample was divided randomly into two subsamples: A (n = 54) and B (n = 46).

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) The second stage involved placement of the experimental assemblage on two active livestock tracks and recording of each artifact’s exposed surface. The experimental plots were measured, georeferenced and photographed (Figure 2). Survey began one year following plot establishment. Each survey, the following observations are recorded: - fractures and/or alterations to each pieces - placement of the exposed face, changes in which provide evidence of trampling even when no other changes are detected - frequency of burial (recorded as 0%; 25%; 50%; 75% of artifact surface) - length of experimental artifact distribution

This experiment was designed to control for several variables in order to improve its comparability with the archaeological record. However, we must acknowledge that there are factors related to both the timescale of the processes involved and the scope and goals of our research that are beyond the control of this experiment. It is important to bear these limitations in mind throughout the experiment, as the results are directly dependent on both controlled and uncontrolled variables. Here, the controlled variables are raw material, substrate and local fauna; the archaeological and the experimental samples are both made on lutite, the substrate is the same due to the fact that both tracks were plotted near T9 and, for this reason, the available fauna is expected to be the same. Uncontrolled variables include the animal that generated each fracture, the action of other taphonomic

89

agents such as water, wind, gravity or snow, and the accumulated effects of these agents over long periods of time.

RESULTS Experimental observations The first survey was conducted one year after the plots were established, at which time it was clear that the animal tracks were still active. All observations were made in the field and the experimental sample left in place for future surveys. The information collected during this first survey shows that: - 32% of the specimens had a new surface exposed (Plot A = 13; Plot B = 19). This is a minimum value since exposed faces may have changed multiple times but only those with the opposite face showing at the time of survey can be recorded as having changed; - 11% of the sample exhibited fractures involving the entire artifact and/or its edge (Plot A = 112); - 9% became partially buried (between 25 and 75% of their surface; Plot A = 4; Plot B = 5); - 9% of the sample could not be relocated (Plot A = 7; Plot B = 2); - the plot’s length increased (horizontal distribution of the sample, parallel to track margins; additional length: Plot A = 12 cm, Plot B = 15 cm); - one piece was found 276 cm away from its original location in Plot A;

Figure 2. Experimental plots on animal tracks. Plot A (Left) and Plot B (Right).

90

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95

Seven percent of the sample exhibited microflaking. Edges with continuous micro-flaking did not exceed 12 mm in length, although a few pieces presented more than one fracture and/or micro-flaking. This suggests that such edge damage can be generated in the short term and that its presence –and therefore flake scar continuity- could be expected to increase over the long run. Features on the edges of specimens in the experimental collection appear in some cases as isolated micro-flaking and in others as continuous flaking with up to six scars (Figure 3). Micro-flaking is usually longer along the edges of pieces (1 to 3 mm) than on their surfaces (1 to 2 mm). Continuous micro-flaking occurs along edges in lengths between 6 and 12 mm and intrudes artifacts’ surfaces 2 mm or less. It is worth mentioning that they always occur as a series of individual flake scars and appear randomly on both sides of specimens. The presence of cattle and horses was recorded near T9 area during fieldwork. This suggests that fauna walked over places where archaeological materials were collected, increasing the chances of lithic artifact trampling. It is also important to note that fresh animal footprints, excrement, and sheep wool were observed on the tracks where the experimental material was placed -very near T9- and, that vegetation was absent from the tracks. All of these characteristics are proxies for recent animal circulation on these tracks, which in turns increases the chances that the experimental sample was trampled. These preliminary results indicate that a single year was enough time for the sample to register changes. These observations highlight the presence of high-energy conditions to which LVA’s surface

archaeological record is currently exposed. One year after the plots were established, 6% of the sample exhibited edge damage or fracture. Maximum fracture thickness recorded was 6 mm. We used this measure as a minimum reference value when analyzing T9 archaeological sample. Conservatively, we proposed that all the fractures present in the archaeological record equal to or less than 6 mm thick could be the result of either taphonomic or anthropic processes.

Archaeological sample Using the experimental data as a reference collection, techno-morphological (Aschero 1975, 1983) and taphonomic aspects of the T9 archaeological sample were analyzed. The following attributes are of particular importance to this study: Fractures (excluding edge damage): 64.18% (n = 172) of the pieces are complete and 35.82% (n = 96) are fractured, including longitudinal split fractures3, which are considered of technological origin (Hiscock 2002). Artifacts with split fractures were excluded for further analysis since their anthropic origin is clear (Figure 4). Excluding split fractures (N = 10), 33.33% of lutite artifacts were broken. Average thickness of broken artifacts: we compared the thickness distributions of split and non-split fractured artifacts. While the distribution of maximum thicknesses in the former is relatively homogeneous, the non-split sample is quite different: 68.60% of the fragmented pieces (N = 59) are up to 6 mm thick (Figure 5). In order to assess the potential of breakage by trampling (Borrazzo 2010; Weitzel 2010; Weitzel et al. 2014), we measured the thickness of the fracture section in pieces with maximum thicknesses greater than 6 mm. The calibrated result is that 76.74% of the s a m p l e c o n ta i n s f r a c t u r e s with thicknesses up to 6 mm (excluding split fractures).

Figure 3. Modifications on experimental artifacts recorded in the first-year survey. A - B: fracture; C - E: edge flaking.

Considering the experimental data presented above, the occurrence of fractures and thicknesses of fractured sections in the T9 archaeological sample does not appear to be random. Fracture frequency increases as specimen thickness decreases. Considering the experimental results, 76.74% of the fractures could be explained by taphonomic processes (specifically trampling) because those pieces exhibit fractures thickness equal to or below

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina)

91

non-anthropic processes on artifact fragmentation -in this case the animal trampling- cannot be rejected either.

Figure 4. Lutite archaeological artifact condition in the T9 sample. Complete (N = 172), fractured (N = 86) and split fracture (known origin) (N = 10), before calibrating the sample.

Micro-flaking (edge damage) and intensity of weathering: the presence of micro-flaking and differences in weathering intensity were analyzed. In all cases, the weathering stage observed on micro-flaking scars was lower than those on the rest of the artifact surface (Figure 1). Of the lutite artifacts (N = 268), 55.60% (N = 149) had flaking and/or micro-flaking on their edges. Among these, recorded weathering stages ranged between 1, 2 or 3 on artifacts surfaces, but 93.96% of the pieces have no weathering on their edges (stage 0) and the remaining 6.04% are minimally weathered (stage 1; Figure 6).

The archaeological lithic collection can be divided into two groups: tools and artifacts with flaked edges. While the tools are clearly of anthropic origin, the artifacts with flaked edges could be the product of taphonomic processes (Figure 1). Flaked edges appear as both isolated and continuous micro-flaking and flaking. The longest flaked edge in the sample is 64 mm. Scar width varies from 3 to 10 mm, and length from 2 to 12 mm. These features always appear as a series of individual flaking scars, Figure 5. Maximum thickness of fractured lutite artifacts (split and non-split and the relation between length and width seems to be random. All of the fractures). tools have marginal unifacially flaked 6 mm; that is, the taphonomic hypothesis cannot edges. The length of these edges ranges from 8 to 82 be rejected for these artifacts. Although we cannot mm, and flake scars are up to 10 mm long. In some completely exclude the possibility that reclamation cases, tools exhibit two- and three-flake-scar series also affected the surface archaeological record, the as well as evidence of edge resharpening. However, experiment provides evidence that the effects of

Figure 6. Weathering stages on the surface of the artifacts with different (lower) weathering on their edges, and weathering stages exhibited by T9 artifact edges.

92

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95

resharpened tool edges present the same weathering stage as the rest of artifact surface (Figure 7).

DISCUSSION As mentioned, observed patterns differ when we consider only the weathering stages on artifacts’ edges relative to artifact bodies. If reclamation for economic purposes did occur, we would expect different (lower) weathering stages (0 to 2) on artifact edges. This is not the case for the T9 archaeological sample, since 93.96% of the pieces have weathering stage 0 on their edges while the remaining 6.04% presents weathering stage 1. In this regard, and returning to the concept of weathering as an indicator of length of exposure, the traces on artifact edges show a relative synchronicity. Furthermore, as their weathering stages suggest, they would have been produced recently. It was also observed that among archaeological artifacts with retouched edges, some instruments show a different pattern (more-than-one-scar series). This difference requires further study since it may help us better understand the processes involved in the formation of the edges. While the results obtained to date do not definitively exclude the possibility of intentional human modification of the archaeological record, they do strengthen arguments in favor of trampling -the intensity of which surely increased during the 100 years since the introduction of European livestock- as the primary process responsible for the observed pattern among surface lithic assemblages. That is, although

we cannot exclude human agency (i.e., reclamation) as a contributor to the weathering patterns described here, the introduction of large herds of cattle during the last hundred years and the relative synchronicity recorded by low weathering stages on flaked edges of T9 stone tools support the taphonomic hypothesis. Furthermore, the average thickness observed among fractured sections in the experimental sample also suggests that a large proportion of those fractures could have been produced by animal trampling.

CONCLUSIONS AND PERSPECTIVES This work began with an archaeological question prompted by a case of equifinality in the LVA archaeological record: Are the patterns we observe in the surface lithic archaeological record the product of anthropic or taphonomic agents? This question guided the development of a research protocol designed to achieve a better understanding of the surface lithic record. In this instance, experimentation has proven fruitful in terms of generating frames of reference for interpreting the LVA surface lithic record. Based on the experimental and archaeological data presented here, the taphonomic hypothesis cannot be rejected. The phenomena observed in the experimental sample were also recorded in the archaeological sample from T9, and comparison of the two samples is appropriate given that we were able to control for several key variables (raw material, substrate, animals presence). Although the results presented here are preliminary, the changes recorded on the experimental collection in a single year suggest that future surveys will yield still more information that will improve our understanding of the potential effects of local taphonomic processes, and clarify whether damage to experimental collections eventually stabilizes (Borrero 1991).

Figure 7. Two tools from T9 archaeological assemblage. Above, a tool with two retouched edges (1: an end-scraper; 2: a side-scraper). Below, a sidescraper and a detail of its retouched edge.

Although the results reported here were obtained from only the first survey, our findings have already proven relevant for determining parameters for analysis and stimulating new lines of inquiry. Specifically, the experimental research led to a hypothesis regarding the origin of patterns observed in the LVA surface lithic assemblages. In accord with other authors (Flegenheimer and Weitzel 2007; Borrazzo 2010; Weitzel 2010; Weitzel et al. 2014), we consider that the thickness of fractures is a sensitive variable in the identification of animal trampling. However, it is important to

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) note that 23.26% of the sample exhibits fractures with an average thickness greater than 6 mm. Fractures of these thicknesses have not been observed in the experimental sample to date, so they may indicate interaction of several different processes on the LVA surface record. These observations and results suggest new avenues of analysis for understanding the LVA record, such as fracture type analysis, which would allow us to identify the origin of fractures on archaeological artifacts (Miller 2006; Weitzel and Colombo 2006; Jennings 2011; Weitzel 2012). Moreover, it is necessary to assess whether there is a direct relationship between edge angles and the occurrence of trampling damage. Also, a more thorough analysis of the edge flaking measurements and morphologies is required to determine whether there are clear morphological patterns useful for distinguishing anthropically from taphonomically flaked edges. Finally, this paper illustrates the utility of actualistic studies to improve our interpretations of the archaeological record. As have other studies (Nielsen 1991; Lopinot and Ray 2007; Eren et al. 2010, 2011; Thiébaut et al. 2010a; Borrazzo 2011a, 2011b; Weitzel et al. 2014), we hope this paper offers a case study in which experimentation generated new data and questions about the formation of the archaeological record, contributing to trampling taphonomic studies and, in particular to the understanding of LVA’s surface lithic assemblages.

Acknowledgments I wish to thank Luis Borrero and Karen Borrazzo for their constant advice and support. Special thanks to Celeste Weitzel who has patiently read and commented on previous versions of this paper and to three anonymous reviewers who helped to improve this paper. I specially thank the Riquez family for their kind support of our archaeological research at La Verdadera Argentina. This study was funded by the Universidad de Buenos Aires (UBACyT 20020100100957) and CONICET (PIP 11220110100262).

REFERENCES Aschero, C. 1975 Ensayo para una clasificación morfológica de artefactos líticos aplicada a estudios tipológicos comparativos. CONICET, Buenos Aires. MS. 1983 Ensayo para una clasificación morfológica de artefactos líticos aplicada a estudios tipológicos comparativos. Apéndices A-C. Revisión. Cátedra de Ergología y Tecnología, Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. MS.

93

Balirán, C. 2012. Preguntas arqueológicas, respuestas actualísticas. Experimentos sobre tafonomía litica al sur de sierra Baguales (Santa Cruz - Argentina). Primeros resultados. Presented at X Jornadas de Jóvenes Investigadores del Instituto Nacional de Antropología y Pensamiento Latinoamericano, Buenos Aires. Borrazzo, K. 2004 Hacia una tafonomía lítica: el análisis tafonómico y tecnológico de los conjuntos artefactuales líticos de superficie provenientes de los loci San Genaro 3 y 4 (Bahía San Sebastián - Tierra del Fuego, Argentina). BD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2006 Tecnología lítica del alero Cerro León 3 (Santa Cruz, Argentina). Magallania 34 (2): 63-74. 2008 Distribuciones artefactuales en la periferia sudeste de la sierra Baguales (Santa Cruz, Argentina). Magallania 36 (1): 103-116. 2010 Arqueología de los esteparios fueguinos. Tafonomía y tecnología lítica en el norte de Tierra del Fuego, Argentina. PhD dissertation. Facultad de Filosofía y Letras. Universidad de Buenos Aires, Buenos Aires. 2011a Tafonomía lítica y pseudoartefactos: el caso de la península El Páramo (Tierra del Fuego, Argentina). Intersecciones en Antropología 12: 155-167. 2011b Tafonomía lítica en la estepa patagónica: experimentación y registro arqueológico de superficie. In Bosques, montañas y cazadores: investigaciones arqueológicas en Patagonia Meridional, compilated by L. A. Borrero and K. Borrazzo, pp. 127-153. CONICETInstituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU), Buenos Aires. Borrero, L. A. 1991 Experimentos y escalas arqueológicas. Shincal 3: 142-148  Borrero, L. A. and K. Borrazzo 2011 La geografía cultural del sudoeste de Patagonia continental. In Bosques, Montañas y cazadores: investigaciones arqueológicas en Patagonia Meridional, compilated by L. A. Borrero y K. Borrazzo, pp. 7-36. CONICET-IMHICIHU, Buenos Aires. Borrero, L. A., N. V. Franco, F. M. Martin, R. Barberena, R. Guichón, J. B. Belardi, C. Favier Dubois and L. L´Heureux 2006 Las Cabeceras del Coyle: información arqueológica y circulación de poblaciones humanas. In Pasado y presente en la cuenca del río Coyle, edited by F. Carballo Marina, J. Belardi and S. Espinosa, pp. 75-95. Universidad Nacional de la Patagonia Austral, Río Gallegos. Burroni, D., R. Donahue, M. Pollard and M. Mussi 2002 The Surface Alteration Features of Flint Artefacts as a Record of Environmental Processes. Journal of Archaeological Science 29: 1277-1287.

94

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95

Eren, M. I., A. Durant, C. Neudorf, M. Haslam, C. Shipton, J. Bora, R. Korisettar and M. Petraglia 2010 Experimental examination of animal trampling effects on artifact movement in dry and water saturated substrates: a test case from South India. Journal of Archaeological Science 37: 3010-3021. Eren, M., A. Boehm, B. Morgan, R. Anderson and B. Andrews 2011 Flaked Stone Taphonomy: a Controlled Experimental Study of the Effects of Sediment Consolidation on Flake Edge Morphology. Journal of Taphonomy 9: 201-217.

Miller, M. J. 2006 An Experimental Study of Lithic Biface Manufacture: Toward Understanding the Perverse Fracture. Master of Arts dissertation. University of Exeter, Exeter. Nielsen, A. E. 1991 Trampling the Archaeological Record: An Experimental Study. American Antiquity 56 (3): 483-503.

Flegenheimer, N. and C. Weitzel 2007 Caminar sobre piedras: los artefactos fracturados de Cerro El Sombrero. XVI Congreso Nacional de Arqueología Argentina, t. III: 263-267. Jujuy.

Osborn, A. J., and R. J. Hartley 1991. Adverse effects of domestic livestock grazing on the archaeological resources of Capitol Reef National Park, Utah. Proceedings of the First Biennial Conference of Research in Colorado Plateau National Parks: 136-153. US Geological Survey, Washington, DC.

Franco, N. V. and L. A. Borrero 2000 Estrategias de utilización de Sierra Baguales. Actas del XIV Congreso Nacional de Arqueología Chilena. Contribución Arqueológica 52: 69-283.

Pargeter, J. 2011 Human and cattle trampling experiments in Malawi to understand macrofracture formation on Stone Age hunting weaponry. Antiquity 85 (327).

Gifford-Gonzalez, D. P., D. B. Damrosch, D. R. Damrosch, J. Prior and R. Thunen 1985 The Third Dimension in Site Structure: an Experiment in Trampling and Vertical Dispersal. American Antiquity 50 (4): 803-818.

Peacock, E. 1991 Distinguishing between Artifacts and Geofacts: A Test Case from Eastern England. Journal of Field Archaeology 18 (3): 345-361.

Hiscock, P. 1985 The need for a taphonomic perspective in stone artefact analysis. Queensland Archaeological Research 2: 82-95. 2002 Quantifying the size of artefact assemblages. Journal of Archaeological Science 29: 251-258. Jennings, T. A. 2011 Experimental production of bending and radial flake fractures and implications for lithic technologies. Journal of Archaeological Science 38: 3644-3651. Kligmann, D. M. 2009 Procesos de formación de sitios arqueológicos: tres casos de estudio en la puna meridional catamarqueña argentina. BAR International Series 1949, Archaeopress, Cambridge. Lopinot, N. and J. Ray 2007 Trampling Experiments in the Search for the Earliest Americans. American Antiquity 72 (4): 771-782. Mcbrearty, S., L. Bishop, T. Plummer, R. Dewar and N. Conard 1998. Tools underfoot: human trampling as an agent of lithic artifact edge modification. American Antiquity 63 (1): 108-122. Merenzon, J. 1988 Perturbaciones en un conjunto lítico depositado sobre valvas: un caso experimental. Asociación de Investigaciones Antropológicas, Buenos Aires. MS.

Pintar, E. 1987 Controles Experimentales de Desplazamiento y Alteración de Artefactos Líticos en Sedimentos Arenosos: Aplicaciones Arqueológicas. BD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. Pryor, J. 1988 The effects of human trample damage on lithics: a consideration of crucial variables. Lithic Technology 17 (1): 45-50. Schiffer, M. 1987 Formation Processes of the Archaeological Record. University of New Mexico Press, Albuquerque. Schoville, B. J. and K. S. Brown 2010 Comparing lithic assemblage edge damage distributions: examples from the late Pleistocene and preliminary experimental results. Vis-à-vis: Explorations in Archaeology 10 (2): 34-49. Thiébaut, C., M-P. Coumont and A. Averbouh 2010a The taphonomic approach: an archaeological necessity. In Mise en commun des approaches en taphonomie. Actes du workshop nº 16-XV e Congress International de I’UISPP, edited by C. Thiébaut, M-P. Coumont and A. Averbouh, pp. 21-28. Société des Amis du Musée National de Préhistoire et de la recherche archéologique, Les Eyzies-de-Tayac-Sireuil.

Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina) Thiébaut, C., M. P. Coumont and A. Averbouh 2010b Approche expérimentale des conséquences du piétinement des grands herbivores sur les vestiges lithiques et osseux. In Mise en commun des approaches en taphonomie. Actes du workshop nº 16-XVe Congress International de I’UISPP, edited by C. Thiébaut, M. P. Coumont, and A. Averbouh, pp. 109-129. Société des Amis du Musée National de Préhistoire et de la recherche archéologique, Les Eyzies-de-Tayac-Sireuil. Weitzel, C. 2010 El estudio de los artefactos formatizados fracturados. Contribución a la comprensión del registro arqueológico y las actividades humanas. PhD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2012 Cuentan los fragmentos. Clasificación y causas de fractura de artefactos formatizados por talla. Intersecciones en Antropología 13: 43-55. Weitzel, C., K. Borrazzo, A. Ceraso and C. Balirán  2014 Trampling fragmentation potential of lithic artifacts: an experimental approach.In this volume, pp. 97-110. 

95

Weitzel, C. and M. Colombo 2006 ¿Qué hacemos con los fragmentos? Un experimento en fractura de artefactos líticos tallados. La Zaranda de Ideas. Revista de Jóvenes Investigadores en Arqueología 2: 19-33. Wilk R. and M. B. Schiffer 1979 The Archaeology of Vacant Lots in Tucson, Arizona. American Antiquity 44 (3): 530-536.

NOTES 1.- Date on bone, (AA98670, dC13 -20.7). 2.- Although artifacts from plot A showed no fractures or damage on their edges in this first survey, in a subsequent survey, conducted in January 2014, broken pieces were recorded in that plot (Fractured N = 2; edge damage N = 6). 3.- Longitudinal split fractures are those that “split the flake into left and right along the percussion axis. Each fragment retains a portion of the platform (often with a portion of the ringcrack in hertzian initiations), and usually a portion of the termination and one lateral margin” (Hiscock 2002: 252).

96

C. Balirán - Intersecciones en Antropología - Volumen especial 1 (2014) 85-95

|

97

Trampling Fragmentation Potential of lithic artifacts: an experimental approach Celeste Weitzel, Karen Borrazzo, Antonio Ceraso and Catalina Balirán Received 20 August 2013. Accepted 11 November 2013

ABSTRACT A proposal to estimate the Trampling Fragmentation Potential (TFP) on lithic artifacts from their metric attributes is presented. We apply a data mining technique known as decision tree to experimental datasets obtained in several trampling experiments. Results show that the ratio of area to thickness is the main element affecting the probability of breakage on lithic artifacts by trampling. Also, a maximum thickness value for lithic artifacts prone to be broken by trampling is estimated. Finally, we argue establishing threshold values for trampling potential allows distinguishing incidental fractures with similar traits and different origins. Keywords: Trampling; Fragmentation potential; Lithics; Experiments; Decision tree.

RESUMEN POTENCIAL DE FRAGMENTACIÓN POR PISOTEO EN ARTEFACTOS LÍTICOS: UNA APROXIMACIÓN EXPERIMENTAL. Este trabajo presenta una propuesta para estimar el Potencial para la Fragmentación por Pisoteo (PFP) en artefactos líticos a partir de los atributos métricos de las piezas. Se aplica la técnica de data mining denominada árbol de decisión, para el análisis de datos experimentales obtenidos en diversas experiencias de pisoteo. Los resultados indican que la razón superficie/espesor es el elemento más influyente sobre la probabilidad de fractura de los artefactos sometidos a pisoteo. De modo complementario, se estima un valor máximo para el espesor de los artefactos líticos que pueden fracturarse por este proceso. Finalmente, el establecimiento de valores límite para la fragmentación por pisoteo permitiría diferenciar fracturas accidentales causadas por otros procesos. Palabras clave: Pisoteo; Potencial de fragmentación; Lítico; Experimentación; Árbol de decisión.

INTRODUCTION Fragmentation is common among lithic assemblage and its causes and implications have been the focus of much archaeological research (i.e., Crabtree 1972; Cotterell and Kamminga 1979; Johnson 1979; Odell 1981; Rondeau 1981; Bergman and Newcomer 1983; Fischer et al. 1984; Hiscock 1985, 2002; Odell and Cowan 1986; Whittaker 1995; Root et al. 1999; Shott

2000; Deller and Ellis 2001; Petraglia 2002; Miller 2006; Weitzel and Colombo 2006; Flegenheimer and Weitzel 2007; Lombard and Pargeter 2008; Tallavaara et al. 2010; Weitzel 2010, 2011, 2012; Jennings 2011, among many others). Lithic artifacts, considered one of the most durable cultural materials, have the potential to bear and preserve valuable information related to the formation of archaeological records (Hiscock 1985; Goldberg et al. 1993; Borrazzo 2004, 2006a,

Celeste Weitzel. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Área Arqueología y Antropología. Municipalidad de Necochea, Av. 10 entre 63 y 67 sin No. (7630), Necochea, Buenos Aires, Argentina. E-mail: [email protected] Karen Borrazzo. CONICET. Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU). Saavedra 15 piso 5° (1083ACA), Buenos Aires. Argentina. Universidad de Buenos Aires. E-mail: [email protected] Antonio Ceraso. Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. Calles 122 y 60 (1900), La Plata, Buenos Aires, Argentina. E-mail: [email protected] Catalina Balirán. Facultad de Filosofía y Letras, Universidad de Buenos Aires. Puán 480 (C1406CQJ), Buenos Aires, Argentina. E-mail: [email protected] Intersecciones en Antropología - Special Issue 1: 97-110. 2014. ISSN 1850-373X Taphonomic Approaches to the Archaeological Record. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina

98

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

2010; Thiébaut et al. 2010a). Artifact fragmentation has been used to assess assemblage preservation and integrity, human occupation intensity, and taphonomic modifications to lithic artifacts themselves (Bordes 1961; Gifford-Gonzalez et al. 1985; Hiscock 1985, 2002; Nielsen 1991; Osborn and Hartley 1991; Borrazzo 2004, 2010; Ramos and Merenzon 2004; Eren et al. 2010, 2011; Thiébaut 2010, among others). Within this framework, we believe that understanding factors that influence lithic artifact breakage is a key issue in need of further investigation. In this paper we define artifact breakage or fragmentation as macroscopic damage (macrofractures) involving the whole artifact, as opposed to edge damage, and the research we present centers on the study of macrofractures. Several archaeological studies have focused on the agents and processes involved in artifact fragmentation. Current archaeological knowledge indicates that lithic artifacts might break as a result of manufacture, use, deliberate breakage, and postdepositional or taphonomic processes (Crabtree 1972; Johnson 1979; Frison and Bradley 1980; Rondeau 1981; Nami 1983; Fischer et al. 1984; Root et al. 1999; Deller and Ellis 2001; Miller 2006; Weitzel and Colombo 2006; Borrazzo 2010; Weitzel 2010, among others). Moreover, the study of fracture surface markings suggests that several patterns of breakage are identifiable as the unequivocal effects of specific processes (Johnson 1979; Frison and Bradley 1980; Fischer et al. 1984; Quinn 2007; Weitzel 2010, 2012). However, bending (transverse) fractures −the most common fracture type in lithic assemblages− may result from a variety of taphonomic processes (Fischer et al. 1984; Cotterell and Kamminga 1987; Whittaker 1995; Weitzel 2010). The low diagnostic power of bending fractures, therefore, has severely limited their usefulness in studies designed to identify causes of lithic fragmentation. Trampling is likely an important cause of lithic fragmentation but the process has been shown to result in numerous bending fractures (Fischer et al. 1984; Cotterell and Kamminga 1987; Whittaker 1995; Flegenheimer and Weitzel 2007; Weitzel 2010, 2012; Jennings 2011). Therefore, understanding the contribution of trampling to overall assemblage fragmentation patterns requires alternative lines of evidence. With this aim, this paper explores methodological tools to gauge the extent of human and faunal trampling in lithic assemblage fragmentation. A crucial first step, and the primary goal of this paper, is to identify which artifacts can and which cannot be broken by trampling. We analyzed relationships between experimentally produced lithic artifacts’ metrics and whether they broke during five independent trampling experiments carried out by the authors. Experimental data is explored with a data mining technique called decision-tree (Quinlan 1986; Williams

2011) and a model with material expectations to asses Trampling Fragmentation Potential is presented.

BACKGROUND Trampling exposes lithic artifacts to complex highenergy processes that can alter both their shape and spatial position. Flakes have morphological attributes that allow us to determine whether their original shape was subsequently modified, which, in turn, permits the study of taphonomic processes that contributed to this modification. Thus, analysis of metric attributes (length, width, and thickness) and the ratios between them among complete artifacts may help us understand the intensity of the post-depositional processes that acted on an assemblage. Several investigations have focused on the processes that can lead to artifact fracture (i.e., Crabtree 1972; Cotterell and Kamminga 1979; Johnson 1979; Odell 1981; Rondeau 1981; Bergman and Newcomer 1983; Fischer et al. 1984; Root et al. 1999; Miller 2006; Weitzel and Colombo 2006; Weitzel 2010). Bordes and Bourgon (1951) were among the first exploring the effects of trampling on lithic assemblages. With the advent of experimental archaeology and studies of site formation processes, several trampling experiments were designed to test specific hypotheses. One of the first such studies was that of Tringham et al. (1974) who proposed a set of criteria for identifying edge damage caused by trampling: random distribution of flake scars, scars on a single surface of the flake, flake scars without patterned orientation or size but always elongated. This paper was discussed later by several researchers who were unable to replicate the results (Flenniken and Haggarty 1980; Mansur-Franchomme 1986; Pryor 1988). Gifford-González et al. (1985) describe an experiment designed to evaluate vertical artifact movements due to human foot traffic. They used a sample of 2000 obsidian flakes ranging in size from 3 to 13 mm and arranged half of them on a loam substrate and the other half on a sandy substrate. Their results showed both a higher fracture rate and the breakage of smaller pieces on the harder substrate (loam). Pintar’s (1987) experiment was designed to track horizontal and vertical displacements due to heavy human foot traffic on surface and subsurface lithic assemblages. She used basalt flakes between 2 and 12 cm, placed on a sandy substrate. Fractures –defined as those thicker than 1 mm- were the least frequent type of damage recorded. Pryor (1988) presents an experiment designed to define material signatures of trampling. The author arranged two sets of artifacts on substrates of different hardness, sandy and loamy. Nine hundred obsidian flakes of different sizes were

Trampling Fragmentation Potential of lithic artifacts: an experimental approach laid on a sandy beach and on a residential garden with loosely compacted loam that included rocks. He found that flakes between 12 mm and 25 mm are resistant to fracture. The experiment focused on edge damage; there are no references to fracture ratios, thickness, or other fracture traits. Jorge Merenzon carried out several experiments in 1983, 1984, and 1986 aimed at controlling the trampling effects of intense human foot traffic on lithic assemblages deposited in shell middens located along the Beagle Channel (Tierra del Fuego, Argentina). He placed lithic artifacts on loamy soils (dry and wet), loamy soils (dry and wet) with shell fragments added, and a fresh, complete shells substrate (dry and wet). In one set of experiments (Merenzon 1988), 511 flakes were deposited in two plots that were trampled for 28 days. The author observed that 90% of the sample was displaced either vertically or horizontally, or both. Regarding macrofactures, he reported that flakes trampled on the complete shell substrate exhibited the highest mass loss (30.5%). In addition, Merenzon observed that both macro- and microfractures were more frequent in the wet plot samples. Finally, he concluded that trampling is a non-linear process and proposed a sequence of three stages, at which particular phenomena predominate: 1) pronounced horizontal dispersal; 2) vertical migration, and 3) edge damage and stability (i.e., no further displacement or breakage while conditions hold). Osborn and Hartley (1991) created twelve experimental plots in Capitol Reef National Park (Utah, USA) to monitor the effects of livestock trampling, specifically post-depositional breakage, artifact visibility, and displacement. Plots included lithic artifacts and ceramic vessel fragments. After approximately six month of livestock grazing, the authors found that only eleven of the 589 original lithic artifacts exhibited fractures and that 22% of the lithic sample recorded horizontal displacement. Nielsen (1991) carried out six experiments to evaluate contradictory results reported by several published trampling experiments. Of his six experiments using obsidian flakes, bone, wood, bricks and sherds, five were conducted on dry consolidated surfaces with no vegetation and one on those same muddy gravel sediments after a heavy rain. The experiments focused mainly on vertical and horizontal displacement, general artifact damage, and patterns of ceramic breakage. Three plots included lithic artifacts. Among them, he assessed three types of damage: breakage, microflaking, and abrasion. Breakage occurred on 19 to 24.8% of the artifacts after trampling and it was more frequent on harder surfaces (24.8%), even though the number of crossings performed on another plot was larger (800 vs. 1500 crossings). McBrearty et al. (1998) designed an experiment to evaluate edge damage due to trampling vs. deliberate

99

retouch. They used 1400 flakes of obsidian and a coarse chert ranging in size from 3 to 7 cm, which were arranged on two different substrates: compact, moist loam and unconsolidated sand. The highest breakage ratio was recorded on high density chert assemblage located on moist loam substrate (39%). The authors concluded that substrate was the most important factor influencing damage, followed by raw material and artifact density. Eren et al. (2010) carried out an experiment to evaluate the effects of short-duration animal trampling on dry and water-saturated substrates. They used 120 limestone flakes that were trampled by buffalos and goats, and recorded horizontal and vertical displacements, artifact inclination, and breakage. The latter occurred only on two artifacts. Thiébaut et al. (2010b) carried out an experiment of bison trampling on flint and chert flakes and bone to evaluate disappearance, spatial displacements, edge modification, and fractures. They observed a fragmentation ratio of nearly 50%. Jennings (2011) conducted three flake fracture experiments testing damage due to manufacture, intentional breakage, and trampling. The goal of the trampling experiment was to break each flake by walking on it. The sample included twenty chert flakes, which were first placed on a dry, hardened silty clay surface with no vegetation cover. Each flake was then stepped on in a single step. Flakes that could not be broken in a single step were subjected to flake-on-flake trampling in which one flake was placed on the silty clay surface, two additional flakes were placed directly on top of it, and all three flakes were stepped on a single time. Nineteen out of twenty flakes were broken during this experiment: eight by a single step (single flake placed on the ground) and eleven during flake-on-flake trampling. The 19 broken flakes exhibited bending, radial, and Hertzian fractures. Bending fractures were the most common (n = 21). The recorded average thickness at break was 3.48 mm in the trampling experiment. Pargeter (2011) assessed human and cattle trampling on dolerite, quartz, and quartzite flakes. Artifacts were placed on sandy clay soil with rock and sand inclusions. In each plot, half of each sample was buried at a depth of 10 cm and the other half was deposited just below the surface, to assess whether fracture occurrence was affected by depth below surface. Cattle (n = 40) trampled the experimental plots for 15 minutes twice a day for 27 days. Human trampling was conducted by six individuals in sock feet, for a period of 1 hour per experiment. The author reported that 2.4% of the sample was broken during cattle trampling while human trampling produced fractures in only 1.5% of the flakes. Pargeter proposed that most fracturing takes place within the first few hours of trampling since, after that time, artifacts are generally covered with sediments and often protected from further fracturing.

100

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

However, nearly 50% of the cattle-broken assemblage was originally located 10 cm below the surface. As this brief review shows, trampling studies focused primarily on: (1) natural/ accidental edge fractures that can simulate intentional retouch or use wear (Tringham et al. 1974; Fischer et. al. 1984; MansurFranchomme 1986; Pryor 1988; McBrearty et al. 1998; Lopinot and Ray 2007; Thiébaut 2010); (2) distinguishing macrofractures originated during production and use from those produced by trampling (McBrearty et al. 1998; Jennings 2011; Pargeter 2011); (3) the extent of horizontal and vertical displacement caused by trampling (GiffordGonzález et al. 1985; Pintar 1987; Merenzon 1988; Eren et al. 2010); and (4) differential rates of fragmentation by raw material type (Nielsen 1991; Osborn and Hartley 1991; McBrearty et al. 1998; Pargeter 2011). Specific traits of trampling fractures have seldom been identified, defined or proposed (Hiscock 1985; Cotterell and Kamminga 1987; Weitzel 2010, 2012; Jennings 2011; Pargeter 2013).

MATERIALS AND METHODS Experiments

Figure 1. Locations of authors’ trampling experiments. 1: Necochea (Buenos Aires); 2: La Verdadera Argentina Ranch archaeological locality (Santa Cruz); 3: Northern Tierra del Fuego.

a hard, compact substrate (brick) and the second one was established on loamy soil in a residential garden (Figure 2). One hour of intense human trampling was performed in each plot by experimenters weighing 50 and 60 kg, one wearing soft-soled shoes and the other wearing socks. Artifact fracture and movement were

Data considered in this study were collected during five experiments in nine plots, carried out by the authors in Buenos Aires, Santa Cruz, and Tierra del Fuego Provinces, Argentina (Figure 1). These experiments involved various lithic raw materials, substrates, trampling agents, Exp RM Substrate and durations (Table 1). The first experiment was carried out by CW and Nora Flegenheimer in Necochea, Buenos Aires Province (Flegenheimer and Weitzel 2007) as part of CW’s dissertation research on lithic artifact fragmentation (Weitzel 2010). Experimental artifacts were manufactured from Sierras Bayas orthoquartzites, the main lithic raw material used by hunter-gatherer groups in the Pampean Region (Flegenheimer et al. 1996; Bayón et al. 2006). One of two plots was established on

Agent Human

t 1 hour

N (fl) 47

N (F) 5

Fth (min/ mean/max)

F%

3/5/7 mm

10.6%

Necochea

Orthoquartzite

Loam Brick

Human

1 hour

52

14

3/5/7 mm

26.9%

LVA steppe

Lutite

Loam with gravels

Fauna

7 years

22

9

1/1.44/4 mm

40.90%

LVA track

Lutite

Loam with gravels

Fauna (livestock)

1 year

46

3

1/3.67/6 mm

6.52%

Loam with gravels

Fauna (livestock)

1 year

54

3

2/3.67/5 mm

5.56%

Fauna

5 years

12

3

2/4/6 mm

20%

Tierra del Fuego

Rhyolite, silicified rocks and lutite

Compact silty clay Wet silty clay

Fauna

5 years

12

0

0

0%

Tierra del Fuego

Finegrained silicified rocks

Compact silty clay

Human

20’

18

1

3 mm

5.55%

Table 1. Summary of the experimental data sets. Ref: Exp: Experiment; RM: raw material; fl: flakes; F: fracture; Fth: fracture thickness.

Trampling Fragmentation Potential of lithic artifacts: an experimental approach

Figure 2. Necochea human trampling experiments. A: brick substrate plot; B: detail of brick substrate after trampling; C: general view of loamy soil plot; D: detail of loamy soil substrate after trampling. Arrows indicate fractured artifacts.

assessed every 10 minutes. Rotations, displacements, and fractures were recorded in both plots at the end of each experiment. Results indicate that fractures were far more common among artifacts in the brick plot (Table 1). In the loamy soil experiment, fragmentation occurred primarily during the first 20 minutes and then plateaued. Breakage ratios among the materials in the brick plot increased throughout the hour; in the last 10-15 minutes breakage was highest among alreadybroken pieces. Finally, all of the fractures were bending type, most of them transverse and perpendicular to the longitudinal axis (Flegenheimer and Weitzel 2007).

101

culpaeus and P. griseus], and hare [Lepus europaeus]) as well as livestock (horse, cow, and sheep) that graze in the area. Experimental artifacts were manufactured from lutite, an immediately available raw material that dominates the local archaeological assemblages (Borrazzo 2006b, 2008).

The second experiment carried out in LVA consisted of two plots established by CB in 2011 (Balirán 2012, 2014). The primary goal of this experiment was to assess fracture patterns of faunal trampling, specifically large cattle. Plots were located on active livestock tracks, away from roads and ranch houses (Figure 4). As in the previous case, all artifacts were manufactured from lutite. The plots were assessed for movement, burial frequency, and fractures in 2012. The final two experiments were developed by KB in northern Tierra del Fuego (Borrazzo 2010, 2013a). The substrate in the study area (aeolian-lacustrine plains, Vilas et al. 1986-1987, 1999; Borrazzo 2012, 2013b)

The other four experiments were developed in Fuego-Patagonia as part of the larger Magallania Archaeological Project directed by Luis Borrero (Borrero 2001a, 2001b). These long-term experiments focus on the study of taphonomic transformations in surface lithic assemblages located within different steppe environments. Two of these experiments were conducted in La Verdadera Argentina Ranch archaeological locality (LVA), in the southeastern Baguales Range (Santa Cruz Province; Borrero et al. 2006, 2007). All of the plots were established on loamy soils containing gravel. One experiment consisted of regular monitoring of a plot first established by KB at the end of 2004 (Borrazzo 2011a), and subsequently revisited in 2005, 2008, 2010, 2011, and 2012 to assess artifact movement, burial frequency, and fracture occurrence (Figure 3). The location of the plot away from roads and ranch houses suggests that main trampling agents are wild fauna (guanaco [Lama guanicoe], puma [Puma concolor], choique Figure 3. LVA steppe plot. A: general view of the environmental setting; B: LVA [Rhea penatta, foxes [Pseudalopex steppe plot; C: detail of plot substrate.

102

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110 is the primary trampling agent (presence of dung and footprint on the plots, guanaco sightings near plots). Finally, a human trampling experiment was conducted near plot A. The experiment included one plot (silty clay substrate) and two agents (55 and 80 kg) wearing rubber-soled shoes. Local lithic raw materials employed for Tierra del Fuego experiments include rhyolite, lutite, and fine-grained silicified rocks. Table 1 summarizes the results of the five experiments presented above and assessed in the following section. It bears noting that only 38 of 263 artifacts broke during the experiments (Figure 6).

Figure 4. LVA animal track experiment (plot A). A: general view of the environmental setting; B: plot A in year 2011; C: detail of track substrate.

is primarily composed of clay (with a small amount of silt). The first experiment in Tierra del Fuego included three plots established in 2007 and assessed in 2008 and 2013. Here we will consider data collected at plots A and C (Borrazzo 2010, Figure 5). Potential trampling agents in the area are guanaco and livestock (cow and sheep) but evidence suggests that guanaco

Analytical Methods

The need for a taphonomic perspective in lithic artifact analysis was first expressed by Hiscock (1985) and has in recent years been acknowledged and applied by an increasing number of scholars (Nash 1993; Paddayya and Petraglia 1993; Burroni et al. 2002; Bordes 2003; Borrazzo 2004, 2006a, 2011a, b; Thiébaut et al. 2010a; Borrero 2011; Domínguez-Rodrigo et al. 2011; Eren et al. 2011, among others). Our theoretical approach is that of lithic taphonomy, which we define as the archaeological and actualistic study of the effects of natural and cultural agents and processes on lithic artifact assemblages that occurred after their deposition in an archaeological context (Borrazzo 2004, 2006a). In studies of site formation processes (Schiffer 1983, 1987), the study of lithic taphonomy focuses on artifact and assemblage morphological and spatial attributes to understand their post-depositional history and paleobiological and paleoenvironmental contexts.

Figure 5. Tierra del Fuego plot A. A: general view of the environmental setting; B: Tierra del Fuego plot A; C: detail of experimental artifact deposited on silty clay substrate.

To assess which variables might explain the observed condition of artifacts −which might have been broken by trampling and which not− we analyzed the maximum length (L), maximum width (W), maximum thickness (T), and raw material of experimental lithic artifacts using R 2.11.0 (R Development Core

Trampling Fragmentation Potential of lithic artifacts: an experimental approach

103

material, trampling agent, and substrate were explicitly detailed in those experiments, the measures for the three main shape axis (length, width, and thickness) of each artifact subjected to trampling were not systematically informed and considered in further analysis. As we will show here, all of these morphometric attributes are a significant factor in fracture occurrence since they condition the fragmentation potential of each artifact and, thus, the expected rate of assemblage fragmentation due to trampling. The statistical characterizations of metric attributes and indices for the experimental data sets considered in our study are summarized in Table 2. The data were analyzed using a data mining technique known as decision trees. Data mining (DM) is defined by Williams (2011) as the science of intelligent data analysis. DM consists in the application of specific algorithms and statistical methods for extracting patterns from large data sets. Technically, it is the process of finding correlations or patterns among dozens of fields in large relational databases (Fayyad et al. 1996; Williams 2011). It is also described as a process of building models, since the information extracted from data is often expressed through models (Williams 2011). Decision trees (DT) are a classic learning system of data mining or knowledge discovery in databases, and a class of statistical methods that generate predictive models. These tree-shaped structures represent sets of decisions; they consist of a root (the most representative attribute that describes the data set); branches (a classification question or probability, one of the possible alternatives or courses of action available at that point); and leaves/ nodes (cases within the dataset, a point where a choice

Figure 6. Examples of broken artifacts from trampling experiments. A-C: LVA livestock track plots; D: LVA steppe plot (drawing below the artifact indicates its original shape and the missing fragment); E-F: Tierra del Fuego plot A; G: Necochea hard surface plot; H: Necochea soft surface plot.

Team 2011). We also included two ratios, maximum length/ maximum width/ maximum thickness (L/W/T) and area to thickness (A/T)1. We previously proposed these rates as potentially significant variables as we observed that absolute artifact measures are not always themselves conclusive on its condition (Borrazzo 2004, 2010; Weitzel 2010). For example, a very thin artifact will not break when subject to trampling if it offers a small surface of encounter (small size). Furthermore, we expected its probability of breakage will also diminish as the difference for its length and width measures approximates to 0 (i.e., similar values for length and width). Finally, we proposed those artifacts exhibiting “spherical shape” (i.e., similar measures for its three shape axis, sensu Zingg 1935) are the less sensitive items to trampling fragmentation (Borrazzo 2004). Thus, we considered L/W/T and/or A/T rates −as possible syntheses of some of the existing relationships among main shape axis− may be significantly related to artifact condition. As evidenced by the studies cited in the literature review and our own experiments, fragmentation ratios are quite variable, even among similar substrates and trampling agents (i.e., Osborn and Hartley 1991; Eren et al. 2010; Thiébaut et al. 2010b; Jennings 2011; Pargeter 2011). We believe this is due in part to the fact that, although  raw

N (observations) Minimum Maximum Mean Median

Max. Length

Max. Width

Max. Thickness

263

263

263

263

263

10

9

2

27.86

.020 .88

74 35.26 35

Area/ Thickness

Length/Width/ Thickness

93

49

427.50

33.66

8.18

151.71

.17

31

7

145.71

.15

Variance

179.05

180.61

21.70

3909.22

.01

Std.dev.

13.38

13.44

4.66

62.52

.12

Table 2. Experimental data set descriptive statistics. All measures in mm.

104

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

must be made) (Berson et al. 1999; Rokach and Maimon 2010; Williams 2011). The system (decision tree) learns from examples in a non-incremental manner: the system is presented with cases relevant to a classification task and it develops a DT from the top down, guided by frequency information in the examples (Quinlan 1986; Berson et al. 1999; Williams 2011). DT inducers are algorithms that automatically construct a DT from a given data set. Specifically, the algorithm seeks to create a tree that explains as perfectly as possible all the available data, that is, to find the optimal DT by minimizing the generalization error (Rokach and Maimon 2010: 151). Algorithms frequently used in DT building include ID3 (Iterative Dicotomiser 3), C4.5 −an extension of ID3− CART (Classification and Regression Tree) and CHAID (Chi Square Automatic Interaction Detection). These algorithms construct a model that explains the given data generating a predictive model by providing a set of rules that can be applied to a new (unclassified) dataset (Quinlan 1986; Palace 1996; Berson et al. 1999). In this work we considered artifact condition (complete or broken) as the target.

RESULTS The decision tree we obtained for the condition of artifacts exposed to trampling is shown in Figure 7. The diagram reads from the top down. According to

the DT, the ratio of artifact area to maximum thickness (A/T) is the first significant variable (root) to explain artifact condition (complete or broken). The decision tree, then, shows −given the variables in our experimental data set− that artifacts with A/T values less than or equal to 172.28 mm were not broken by trampling. Thus, the condition of approximately 91% of the experimental dataset (unbroken) is explained by the model. The first node (following the right branch) indicates that artifacts with an A/T greater than 172.28 mm were broken after trampling when their length/ width/thickness ratio (L/W/T) was greater than or equal to 0.28. If L/W/T is smaller than 0.28 (left branch of the first node) the DT produces a second node where length is the decisive variable: artifacts equal to or longer than 35.5 mm remained unbroken after being trampled (left branch of the second node), while shorter artifacts are evaluated by another condition, indicated in the third node (right branch). Here, A/T becomes important again since short artifacts (L < 35.5) with A/T values below 210.6 mm should not break when subjected to trampling (left branch of the third node), but should break if A/T is greater than or equal to 210.6 mm. In order to assess if the relationships between artifact condition and the variables selected by the DT were statistically significant, we perform a Student´s t-test for artifact condition against each DT variable. Results show that the relationship between A/T and artifact condition is the only statistically significant (see Table 3). Therefore, factors other than A/T may change their role in the model as new data is submitted to the decision tree. Still, although we do not expect the role of A/T to change, its “switch-point” values may change as new data or datasets are considered. The DT presented here will only be useful for samples holding metric values and raw materials similar to the ones in our experimental data set. Next we included in the decision tree the contextual variables shown by our trampling experiments to affect damage outcomes; particularly trampling agent and substrate. Considering all the variables together (raw material, metric, and contextual), the decision tree arrived at exactly the same structure for trampling expectations. That is, raw material, agent, and substrate were not selected by DT as determining factors for artifact condition after trampling events. It is worth

Figure 7. Decision tree for the condition of experimental artifacts subject to trampling.

Thickness Length Width Area Area/Thickness Length/Width/Thickness

p .08 .054 .55 .39 .00007 .24

T 1.72 -1.96 -.59 -.85 -3.6 -1.16

Table 3. Student`s t-test for artifact condition (significance level: .05).

Trampling Fragmentation Potential of lithic artifacts: an experimental approach

105

considering that the influence of raw material may increase with obsidian artifacts because of its high fragility. Further experimentation is needed to assess this statement.

propose for artifact TFP assessment derives from our actualistic observations: thickness. Given our dataset, artifacts whose sections are up to 7 mm thick can be broken by trampling and therefore have high TFP.

So far, DT selected A/T ratio as the key variable affecting artifact condition when subjected to trampling. Student’s t test showed that the relation between these variables is the only statically significant. Furthermore, DT predicts that artifacts exhibiting A/T values below 172.28 mm are unlikely to be broken by trampling. Thus, DT predictions suggest that the occurrence of fractures on pieces exhibiting smaller A/T values should be attributable to other processes. Based on these results, we propose that the ratio of area to thickness is a key in the assessment of trampling fragmentation potential (TFP) in lithics. Our results indicate that TFP is primarily conditioned by artifacts’ metric attributes and that other factors such as substrate and trampling agent may influence the frequency of fragmentation but not whether an artifact can be broken by trampling. For example, the results from the Necochea experiment showed that there was a significant relationship between substrate hardness and fracture ratio (Weitzel 2010), as demonstrated previously by other researchers (Gifford-Gonzalez et al. 1985; Nielsen 1991; McBrearty et al. 1998). A further important observation from our study is that in none of the experiments fracture section thicknesses of more than 7 mm were recorded. Therefore, we propose to add thickness as a complementary variable to assess artifact TFP. If we consider 7 mm the maximum thickness that can be effectively broken by trampling given the other morphological characteristics represented in our experimental dataset, then tentatively, we can suggest that any artifact with an A/T value above 172.28 and 7 mm or more thick cannot be broken by trampling. Of course, the 7 mm thickness threshold is based on trampling agents weighting up to approximately 600 kg; agents above this weight (i.e., elephants or several extinct mammals, Borrero and Martin 2012) might break artifacts 7 mm thick; further actualistic research is required in areas that include or included such large-bodied animals.

These threshold values explain artifact condition for the dataset obtained from our five trampling experiments, but the DT also serves as a predictive model. That is, we can evaluate new data (experimental or archaeological) relative to this model, so long as it is within the morphological range, and suite of raw materials, substrates and agents. Meeting these criteria, the model will predict artifacts’ condition (broken or whole), and we can then compare artifact’s actual condition to the modeled predictions to assess whether trampling is the most likely mechanism to explain the fragmentation pattern observed in any given assemblage. Furthermore, the model can be refined with new experimental data; as it incorporates more “training” data, the model’s predictions become more accurate and applicable to more diverse assemblages. The DT also shows that, among our sample, other variables (length/width/thickness and artifact length) contribute to artifact condition, though they are not statistically significant. The size of the available sample remains small, and the role of these variables in explaining artifact condition may change as more data are introduced to the DT. We will be better able to judge the relative importance of these and other variables when the available experimental sample is diverse enough to represent the morphological universe of flaked artifacts. The model presented above is useful for assessing lithic assemblages with attributes (metric variables and raw materials) similar to those considered in our data set (Table 2), but assemblages exhibiting different values for artifact morphometric attributes are not strictly comparable and therefore specific experimental data are needed for the construction of a new DT.

DISCUSSION Based on the results of our analyses using decision trees and experimental observations of attributes that influence lithic artifact breakage by trampling, we propose two threshold values for assessing TFP. The first is the ratio of area to thickness, selected as the DT root for predicting artifact condition (threshold value for current sample is 172.28 mm). So far, A/T is the only variable among those considered for this study exhibiting a statistically significant relationship with artifact condition. The second threshold value we

We recommend a cautious use of threshold values to assess whether a lithic assemblage was subjected to trampling by calculating the frequency of whole flakes with a high TFP (here, A/T >172.28 mm and maximum thickness < 7 mm). If a sample contains intact artifacts with a high TFP, that lithic assemblage may not have been intensively affected by trampling processes. On the other hand, if high TFP flakes are scarce or absent from an assemblage, the analyst will need to determine whether such artifacts were ever present in the original assemblage before making a claim for trample damage since flake morphological attributes depend on tool production techniques and parent material size. To address this, we suggest a thorough examination of broken flakes to understand an assemblage’s original composition (Hiscock 2002). Lastly, TFP expectations provided by the model permit special consideration of broken artifacts with fracture thicknesses greater than

106

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

7 mm. In this case, fracture-type analyses might help us distinguish fractures generated through production technique, knapping errors, or deliberate breakage (Weitzel 2010).

CONCLUDING REMARKS AND PERSPECTIVES The decision tree technique generated a model that explains and predicts the attributes that determine lithic artifact breakage by trampling. The model predicts the condition of an artifact (broken or whole) after trampling based on its metric attributes and their relationships. Given these predictions, we can interpret the likelihood that trampling was a leading cause of artifact fragmentation in a given assemblage. Moreover, the model can be trained with new datasets, which will improve the accuracy of its predictions. It is worth repeating that the dataset used to generate the critical A/T and length values reported here was relatively small. A more diverse sample is necessary to generate an A/T threshold applicable to any lithic assemblage. Nonetheless, this exploratory research suggests a promising new avenue for trampling fragmentation research which may ultimately generate threshold values able to evaluate both the causes that originated fragmentation in given lithic assemblages and the impact of trampling. In addition, the accuracy of the A/T values can be adjusted to specific contexts by generating large experimental datasets for the specific context under study, that is, by replicating the archaeological substrate, potential trampling agents, and lithic artifact morphometric attributes. Finally, we suggest that future work to improve our knowledge of lithic artifact fragmentation due to trampling requires: increasing the experimental sample; increasing the sample’s diversity (different artifact morphologies, lithic raw materials, substrates, etc.); adding new variables and reporting the morphometric characteristics of experimental datasets subjected to trampling as a standard in trampling experiments. Trampling and its effects have been a frequent topic in actualistic research in archaeology. However, further work is necessary to improve our knowledge of the complex processes that lead to the fragmentation patterns seen in archaeological assemblages worldwide.

Aknowledgements The authors wish to thank Nora Flegenheimer and Luis Alberto Borrero for their careful reading and support. Three reviewers and Raven Garvey’s comments and suggestion improved this paper. This study was funded by CONICET, ANPCyT, and Universidad de Buenos Aires.

REFERENCES Balirán, C. 2012 Preguntas arqueológicas, respuestas actualísticas. Experimentos sobre tafonomía lítica al sur de sierra Baguales (Santa Cruz-Argentina). Primeros resultados. Presented at X Jornadas de Jóvenes Investigadores del INAPL, Buenos Aires. 2014 Trampling, taphonomy, and experiments with lithic artifacts in the southeastern Baguales Range (Santa Cruz, Argentina). In this volume, pp. 85-95. Bayón, C., N. Flegenheimer and A. Pupio 2006 Planes sociales en el abastecimiento y traslado de roca en la Pampa bonaerense en el Holoceno Temprano y Tardío. Relaciones de la Sociedad Argentina de Antropología XXXI: 19-27. Bergman, C. A. and M. H. Newcomer 1983 Flint Arrowhead Breakage: Examples from Ksar Akil, Lebanon. Journal of Field Archaeology 10: 238-243. Berson, A., S. Smith and K. Thearling 1999 Building Data Mining Applications for CRM. McGraw-Hill, New York. Bordes, F. 1961 Typologie du Paléolithique Ancien et Moyen. Institut de préhistoire de l’université de Bordeaux, Bourdeaux. Bordes, J. G. 2003 Lithic taphonomy of the Chatelperronian/ Aurignacian interstratifications in Roc de Combe and Le Piage (Lot, France). In The chronology of the Aurignacian and of the transitional technocomplexes: dating, stratigraphies, cultural implications, Trabalhos de Arqueologia 33, edited by J. Zilhão and F. D’Errico, pp. 223-244. Instituto Português de Arqueologia, Lisboa. Bordes, F. and M. Bourgon 1951 Le complexe moustérien: Moustériens, Levalloisien et Tayacien. L’Anthropologie 55: 1-23. Borrazzo, K. 2004 Hacia una tafonomía lítica: el análisis tafonómico y tecnológico de los conjuntos artefactuales líticos de superficie provenientes de los loci San Genaro 3 y 4 (Bahía San Sebastián - Tierra del Fuego, Argentina). Undergraduate thesis. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2006a Tafonomía lítica en dunas: una propuesta para el análisis de los artefactos líticos. Intersecciones en Antropología 7: 247-261. 2006b Tecnología lítica del alero Cerro León 3 (Santa Cruz, Argentina). Magallania 34 (2): 63-74. 2008 Distribuciones artefactuales en la periferia sudeste de la sierra Baguales (Santa Cruz, Argentina). Magallania 36 (1): 103-116.

Trampling Fragmentation Potential of lithic artifacts: an experimental approach Borrazzo, K. 2010 Arqueología de los esteparios fueguinos. Tafonomía y tecnología lítica en el norte de Tierra del Fuego, Argentina. PhD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. 2011a Tafonomía lítica en la estepa patagónica: experimentación y registro arqueológico de superficie. In Bosques, Montañas y cazadores: investigaciones arqueológicas en Patagonia Meridional, compiled by L. A. Borrero and K. Borrazzo, pp. 127-153. CONICETIMHICIHU, Buenos Aires. 2011b Tafonomía lítica y pseudoartefactos: el caso de la península El Páramo (Tierra del Fuego, Argentina). Intersecciones en Antropología 12: 155-167. 2012 Raw material availability, flaking quality and hunter-gatherer decision making in Northern Tierra del Fuego Island (Argentina). Journal of Archaeological Science 39: 2643-2654. http://dx.doi.org/10.1016/j. jas.2012.03.018 2013a Tafonomía lítica y modelo de la dinámica eololacustre del norte de la bahía San Sebastián (Tierra del Fuego, Argentina). Comechingonia 17 (1): 149-169. 2013b Tecnología lítica y disponibilidad de materias primas en el norte de Tierra del Fuego (Argentina). In Tendencias teórico-metodológicas y casos de estudio en la arqueología de Patagonia, edited by A. F. Zangrando, R. Barberena, A. Gil, G. Neme, M. Giardina, L. Luna, C. Otaola, S. Paulides, L. Salgán and A. Tivoli, pp. 569-576. Museo de Historia Natural de San Rafael, Sociedad Argentina de Antropología e Instituto de Antropología y Pensamiento Latinoamericano, San Rafael. Borrero, L. A. 2001a Regional Taphonomy: The Scales of Application to the Archaeological Record. In Animals and Man in the Past. Essays in honour of Dr. A. T. Clason, edited by H. Buitenhuis and W. Prummel, pp. 17-20. ARCPublicatie 41, Groningen. 2001b Regional Taphonomy: Background Noise and the Integrity of the Archaeological Record. In Ethnoarchaeology of Andean South America: Contributions to Archaeological Method and Theory, edited by L. A. Kuznar, pp. 243-254. International Monographs in Prehistory, Ethnoarchaeological Series 4, Ann Arbor. 2011 La función transdisciplinaria de la arqueozoología en el siglo XXI: restos animales y más allá. Antípoda 13: 267-274. Borrero, L. A., N. V. Franco, F. M. Martin, R. Barberena, R. Guichon, J. B. Belardi, C. Favier Dubois and L. L´Heureux 2006 Las Cabeceras del Coyle: información arqueológica y circulación de poblaciones humanas. In Pasado y presente en la cuenca del río Coyle, edited by F. Carballo Marina, J. Belardi and S. Espinosa, pp. 75-95. Universidad Nacional de la Patagonia Austral, Río Gallegos.

107

Borrero, L., R. Barberena, F. Martin and K. Borrazzo 2007 Collapsed Rockshelters in Patagonia. In On Shelter’s Ledge: Histories, Theories, and Methods of Rockshelter Research, edited by M. Kornfeld, Sergey Vasilev and L. Miotti, pp. 135-139. BAR International Series 1655. Archaeopress, Oxford. Borrero, L. A. and F. Martin 2012 Ground sloths and humans in southern FuegoPatagonia: taphonomy and archaeology. World Archaeology 44 (1): 102-107. Burroni, D., R. Donahue, M. Pollard and M. Mussi 2002 The Surface Alteration Features of Flint Artefacts as a Record of Environmental Processes. Journal of Archaeological Science 29: 1277-1287. Cotterell, B. and J. Kamminga 1979 The Mechanics of Flaking. In Lithic use-wear analysis, edited by B. Hayden, pp. 97-112. Academic Press, New York. 1987 The Formation of Flakes. American Antiquity 52 (4): 675-708. Crabtree, D. E. 1972 An Introduction to Flintworking. Occasional Papers 28. State University Museum, Pocatello, Idaho. Deller, D. B. and C. J. Ellis 2001 Evidence for Late Paleoindian Ritual from the Caradoc Site (AfHj-104), Southwestern Ontario, Canada. American Antiquity 66 (2): 267-284. Domínguez-Rodrigo, M., S. Fernández-López and L. Alcalá 2011 How can taphonomy be defined in the XXI Century? Journal of Taphonomy 9: 1-13. Eren, M. I., A. Durant, C. Neudorf, M. Haslam, C. Shipton, J. Bora, R. Korisettar and M. Petraglia 2010 Experimental examination of animal trampling effects on artifact movement in dry and water saturated substrates: a test case from South India. Journal of Archaeological Science 37: 3010-3021. Eren, M., A. Boehm, B. Morgan, R. Anderson and B. Andrews 2011 Flaked Stone Taphonomy: a Controlled Experimental Study of the Effects of Sediment Consolidation on Flake Edge Morphology. Journal of Taphonomy 9: 201-217. Fayyad, U., G. Piatetsky-Shapiro and P. Smyth 1996 From Data Mining to Knowledge Discovery in Databases. American Association for Artificial Intelligence: 37-54. Fisher, A., P. Vemming Hansen and P. Rasmussen 1984 Macro and Micro-Wear Traces on Lithic Projectile Points. Experimental Results and Prehistoric Examples. Journal of Danish Archaeology 3: 19-46.

108

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

Flegenheimer, N. and C. Weitzel 2007 Caminar sobre piedras: los artefactos fracturados de Cerro El Sombrero. XVI Congreso Nacional de Arqueología Argentina t. III: 263-267. Jujuy. Flegenheimer, N., S. Kain, M. Zárate and A. Barna 1996 Aprovisionamiento de cuarcitas en Tandilia, las canteras de Arroyo El Diamante. Arqueología 6: 117-141. Flenniken, J. J. and J. C. Haggarty 1980 Trampling as an Agency in the Formation of Edge Damage: An Experiment in Lithic Technology. Northwest Anthropological Research Notes 13 (2): 208-214. Frison, G. C. and B. K. Bradley 1980 Folsom Tools and Technology at the Hanson Site, Wyoming. New Mexico Press, New Mexico University. Gifford-Gonzalez, D. P., D. B. Damrosch, D. R. Damrosch, J. Prior and R. Thunen 1985 The Third Dimension in Site Structure: an Experiment in Trampling and Vertical Dispersal. American Antiquity 50 (4): 803-818. Goldberg, P., D. T. Nash and M. D. Petraglia (editors) 1993 Formation Processes in Archaeological Context. Monographs in World Prehistory 17. Prehistory Press, Madison. Hiscock, P. 1985 The need for a taphonomic perspective in stone artefact analysis. Queensland Archaeological Research 2: 82-95. 2002 Quantifying the size of artefact assemblages. Journal of Archaeological Science 29: 251-258. Jennings, T. A. 2011 Experimental production of bending and radial flake fractures and implications for lithic technologies. Journal of Archaeological Science 38: 3644-3651. Johnson, J. K. 1979 Archaic Biface Manufacture Production Failures. A Chronicle of the Misbegotten. Lithic Technology 10: 25-35. Lombard, M. and J. Pargeter 2008 Hunting with Howiesons Poort segments: pilot experimental study and the functional interpretation of archaeological tools. Journal of Archaeological Science 35: 2523-2531. Lopinot, N. and J. Ray 2007 Trampling Experiments in the Search for the Earliest Americans. American Antiquity 72 (4): 771-782. Mansur-Franchomme, M. E. 1986 Microscopie du materiel lithique préhistorique: traces d’utilisation, alterations naturelles, accidentelles et technologiques. Cahiers du Quaternarie 9, Bordeaux.

McBrearty, S., L. Bishop, T. Plummer, R. Dewar and N. Conard 1998 Tools underfoot: human trampling as an agent of lithic artifact edge modification. American Antiquity 63 (1): 108-122. Merenzon, J. 1988 Perturbaciones en un conjunto lítico depositado sobre valvas: un caso experimental. Buenos Aires, Asociación de Investigaciones Antropológicas. MS. Miller, M. J. 2006 An Experimental Study of Lithic Biface Manufacture: Toward Understanding the Perverse Fracture. MA dissertation. University of Exeter, Exeter. Nami, H. G. 1983 La experimentación aplicada a la interpretación de artefactos bifaciales: un modelo de manufactura de puntas de proyectil de los niveles inferiores del Alero Cárdenas, Provincia de Santa Cruz. Undergraduate thesis. Facultad de Filosofía y Letras, Universidad de Buenos Aires. Nash, D.T. 1993 Distinguishing Stone Artifacts from Naturefacts created by Rockfall Processes. In Formation Processes in Archaeological Context, edited by P. Goldberg, D. T. Nash and M. D. Petraglia, pp. 125-138. Monographs in World Prehistory 17. Prehistory Press, Madison. Nielsen, A. E. 1991 Trampling the Archaeological Record: An Experimental Study. American Antiquity 56 (3): 483-503. Odell, G. H. 1981 The Mechanics of Use-Breakage of Stone Tools: Some Testable Hypotheses. Journal of Field Archaeology 8: 197-209. Odell, G. H. and F. Cowan 1986 Experiments with Spears and Arrows on Animal Targets. Journal of Field Archaeology 13 (2): 195-212. Osborn, A. J., and R. J. Hartley 1991 Adverse effects of domestic livestock grazing on the archaeological resources of Capitol Reef National Park, Utah. Proceedings of the First Biennial Conference of Research in Colorado Plateau National Parks: 136-153. US Geological Survey, Washington, DC. Paddayya, K. and M. Petraglia 1993 Formation Processes of Acheulian Localities in the Hunsgi and Baichbal Valleys, Peninsular India. In Formation Processes in Archaeological Context, edited by P. Goldberg, D. T. Nash and M. D. Petraglia, pp. 61-82. Monographs in World Prehistory 17. Prehistory Press, Madison.

Trampling Fragmentation Potential of lithic artifacts: an experimental approach Palace, B. 1996 Data Mining. Technology Note prepared for Management 274A. Anderson Graduate School of Management at UCLA. Pargeter, J. 2011 Human and cattle trampling experiments in Malawi to understand macrofracture formation on Stone Age hunting weaponry. Antiquity 85 (327).  2013 Rock type variability and impact fracture formation: working towards a more robust macrofracture method. Journal of Archaeological Science. http://dx.doi. org/10.1016/j.jas.2013.05.021 (consulted 17 july 2013). Petraglia, M. D. 2002 The heated and the broken: thermally altered stone, human behavior, and archaeological site formation. North American Archaeologist 23 (3): 241-269. Pintar, E. 1987 Controles experimentales de desplazamientos y alteraciones de artefactos líticos en sedimentos arenosos: Aplicaciones arqueológicas. Undergraduate thesis. Facultad de Filosofía y Letras, Universidad de Buenos Aires, Buenos Aires. Pryor, J. 1988 The effects of human trample damage on lithics: a consideration of crucial variables. Lithic Technology 17 (1): 45-50. Quinn, G. D. 2007 Fractography of Ceramics and Glasses. National Institute of Standards and Technology, Special Publication 960-16. U.S. Government Printing Office, Washington. Quinlan, J. R. 1986 Induction of Decision Trees. Machine Learning 1: 81-106. R Development Core Team 2011 R: A language and environment for statistical computing, reference index version 2.2.1. URL. R Foundation for Statistical Computing, Vienna, Austria, http://www.R-project.org. Ramos, M and J. Merenzon 2004 Ensamblajes, tecnología lítica y análisis espacial del Primer Componente de Túnel I. In Temas de arqueología. Análisis lítico, compiled by A. Acosta, D. Loponte and M. Ramos, pp. 145-191. Universidad Nacional de Luján, Luján. Rokach, L. and O. Maimon 2010 Classification trees. In Data Mining and Knowledge Discovery Handbook, edited by Maimon O. and L. Rokach, pp. 165-192. Springer, New York. Rondeau, M. 1981 An Additional Failure Type During Biface Manufacture. Lithic Technology 10: 10-11.

109

Root, M. J., J. D. William, M. Kay and L. K. Shifrin 1999 Folsom Ultrathin Biface Radial Break Tools in the Knife River Flint Quarry Area. In Folsom Lithic Technology, edited by D. Amick, pp. 144-168. International Monographs in Prehistory, Archaeological Series 12, Ann Arbor, Michigan. Schiffer, M. 1983 Toward the Identification of Formation Processes. American Antiquity 48 (4): 675-706. 1987 Formation Processes of the Archaeological Record. University of New Mexico Press, Albuquerque. Shott, M. J. 2000 The Quantification Problem in Stone-Tool Assemblages. American Antiquity 65 (4): 725-738. Tallavaara, M., M. A. Manninen, E. Hertell and T. Rankama 2010 How flakes shatter: a critical evaluation of quartz fracture analysis. Journal of Archaeological Science 37: 2442-2448. Thiébaut, C. 2010 Denticulate Mousterian: myth or reality? Acta Universitatis Wratislavensis 3207. Studia Archaeologiczne XLI: 345-386. Thiébaut, C., M-P. Coumont and A. Averbouh 2010a The taphonomic approach: an archaeological necessity. In Mise en commun des approaches en taphonomie. Actes du workshop nº 16-XVe Congress International de I’UISPP, edited by C. Thiébaut, M-P. Coumont and A. Averbouh, pp. 21-28. Société des Amis du Musée National de Préhistoire et de la recherche archéologique, Les Eyzies-de-Tayac-Sireuil. Thiébaut, C., M-P. Coumont and A. Averbouh 2010b Approche expérimentale des conséquences du piétinement des grands herbivores sur les vestiges lithiques et osseux. In Mise en commun des approaches en taphonomie. Actes du workshop nº 16-XVe Congress International de I’UISPP, edited by C. Thiébaut, M. P. Coumont and A. Averbouh, pp. 109-129. Société des Amis du Musée National de Préhistoire et de la recherche archéologique, Les Eyzies-de-Tayac-Sireuil. Tringham, R., G. Cooper, G. Odell, B. Voytek and A. Whitman 1974 Experimentation in the Formation of Edge Damage: A New Approach to Lithic Analysis. Journal of Field Archaeology 1: 171-196. Vilas, F. E., A. Arche, M. Ferrero, G. Bujalesky, F. Isla and G. González Bonorino 1986-1987 Sedimentación intermareal en Bahía San Sebastián, Tierra del Fuego, Argentina. Acta Geológica Hispánica 21-22: 253-260. Vilas, F. E., A. Arche, M. Ferrero and F. Isla 1999 Subantarctic macrotidal flats, cheniers and beaches in San Sebastian Bay, Tierra del Fuego, Argentina. Marine Geology 160: 301-326.

110

C. Weitzel et al.- Intersecciones en Antropología - Special Issue 1 (2014) 97-110

Weitzel, C. 2010 El estudio de los artefactos formatizados fracturados. Contribución a la comprensión del registro arqueológico y las actividades humanas. PhD dissertation. Facultad de Filosofía y Letras, Universidad de Buenos Aires. 2011 Rotura intencional de artefactos líticos formatizados en la Región Pampeana Bonaerense. Revista del Museo de Antropología 4: 47-64. 2012 Cuentan los fragmentos. Clasificación y causas de fractura de artefactos formatizados por talla. Intersecciones en Antropología 13: 43-55. Weitzel, C. and M. Colombo 2006 ¿Qué hacemos con los fragmentos? Un experimento en fractura de artefactos líticos tallados. La Zaranda de Ideas. Revista de Jóvenes Investigadores en Arqueología 2: 19-33.

Whittaker, J. C. 1995 Flintknapping. Making and Understanding Stone Tools. Austin, University of Texas Press. Williams, G. 2011 Data Mining with Rattle and R. The Art of Excavating Data for Knowledge Discovery. Springer. Zingg, T. 1935 Beitrag zur schotteranalyse. Schweizerisch Mineralogie und Petrologie Mitterwald 15: 39-140.

NOTES 1. Area=L x W; L= artifact maximum length (in mm); W=artifact maximum with (in mm). All measures were made with a digital caliper.

Lihat lebih banyak...

Comentarios

Copyright © 2017 DATOSPDF Inc.