Author's personal copy Global and Planetary Change 69 (2009) v–vii
Contents lists available at ScienceDirect
Global and Planetary Change j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / g l o p l a c h a
Introduction to Cenozoic Antarctic glacial history
1. Introduction Fluctuations in size of the Antarctic Ice Sheet (AIS), a feature of the southern high latitudes for at least the last 35 million years, have been one of the major driving forces of changes in global sea level and climate through the Cenozoic Era. Under the prospect of a warming climate (IPCC, 2007), it is important to assess the past and future stability of the cryosphere, particularly after ice core records identified a direct link between variations in CO2 concentration in the atmosphere and palaeotemperatures. This special issue of Global and Planetary Change developed largely from contributions presented at the EGU meeting in Vienna, Austria (http://meetings.copernicus.org/egu2008/; 13–18 April, 2008), and at the International Geological Congress (IGC) Conference in Oslo, Norway (www.33igc.org/; 6–14 August, 2008) where we organised sessions designed to investigate the many orders and scales of variation of Antarctic ice sheets and palaeoclimate from Antarctic and Subantarctic records, from outcrop studies, deep sea drilling, continental margin drilling and seismic investigations, permafrost and ice core drilling. This special issue of Global and Planetary Change continues a series of related special issues and a book (Florindo et al., 2003, 2005; Barrett et al., 2006; Florindo et al., 2008; Florindo and Siegert, 2009), all of which are linked to the Antarctic Climate Evolution (ACE) project. ACE is an initiative of the Scientific Committee on Antarctic Research (SCAR) to investigate the climate and glacial history of Antarctica by linking climate and ice sheet modelling studies with terrestrial and marine geological and geophysical evidence of past changes (www.scar.org/researchgroups/geoscience/ace; http://www. ace.scar.org). Over the coming years, ACE will pursue a broad range of objectives to better comprehend past Antarctic changes through organisation of workshops and publication of special issues, allowing the dissemination of geological data and numerical modelling to a wide audience. 2. Organisation and volume content Papers presented in this special issue provide specific information on palaeoenvironments and palaeoclimates in Antarctica and the Southern Ocean during the Cenozoic; this information comes largely from seismic research, drilling and coring. Fig. 1 shows the general locations of studies presented in this issue. The Antarctic Geological Drilling (ANDRILL) Program, a multinational collaboration of scientists, students, and educators from four nations (Germany, Italy, New Zealand and the United States) designed to recover stratigraphic records from the Antarctic continental margin, is the focus of 6 of these papers equally distributed between 0921-8181/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.gloplacha.2009.11.001
the McMurdo Ice Shelf (MIS) record (Dunbar et al., 2009-this issue; Giorgetti et al., 2009-this issue; Talarico and Sandroni, 2009-this issue) and the Southern McMurdo Sound (SMS) record (Atkins and Dunbar, 2009-this issue; Del Carlo et al., 2009-this issue; Marcano et al., 2009-this issue). During the austral summer of 2006–2007, the ANDRILL-MIS Project recovered a 1285-m-long record of climate and ice sheet variability spanning the past 13 million years from beneath the MIS (e.g. Naish et al., 2007). Dunbar et al. (2009-this issue) analysed a 19.8-m-long firn core from the MIS for dust concentration in order to quantify the annual flux of sediment onto the MIS at Windless Bight, examine its temporal variability and calculate its contribution to subice shelf sedimentation. By using a simple ice flow model to calculate basal melt rates, and hence dust flux through the ice shelf, they highlight the importance of the proximity of the calving (or grounding) lines for the supply of fine-grained sediment to the subice shelf cavity. The following two papers address the problem of the provenance signatures of the Antarctic Ice Sheets in the Ross Embayment. In order to improve the understanding of the Late Pleistocene variation in ice dynamics in the McMurdo area, Giorgetti et al. (2009-this issue) investigated the clay and heavy mineral assemblages of the late Pleistocene subglacial and glaciomarine sediments in the MIS Project AND-1B drill core. The analyses show that the sediments are a mix of detritus from the McMurdo Volcanic Group (prevailing) and the Transantarctic Mountains from the south and west, with fluctuations determined by changes in the source rocks and sedimentary processes. During open marine (interglacial) conditions only sediments from a local source (i.e. McMurdo Volcanic Group) were deposited. The paper by Talarico and Sandroni (2009-this issue) provides quantitative results based on logging of the gravel fraction and on the petrographic characterisation of intrusive and metamorphic clasts present in the lowermost section (below 400 mbsf) of the AND-1B core, which span in time from Middle Miocene (ca. 13 Ma) to Early Pliocene (ca. 3.5 Ma). Long-term shifts in compositional patterns outline an evolving provenance that is interpreted to reflect the combined effects and complex interactions among variations in ice volume, ice flow patterns and paleogeographic changes linked to the local tectonic and volcanic activity. The next three papers report new data from the ANDRILL SMS Project, which complements the results of the first drilling season (ANDRILL-MIS) by penetrating deeper into the stratigraphic section in the Victoria Land Basin and extending the recovered time interval back to approximately 20 million years ago (e.g. Harwood et al., 2009). Marcano et al. (2009-this issue) report on Strontium isotope investigation from selected Miocene to Pleistocene macrofossil
Author's personal copy vi
F. Florindo et al. / Global and Planetary Change 69 (2009) v–vii
Fig. 1. Polar stereographic projection to 30°S with general locations of areas studied in this issue. Abbreviations of locations: AP, Antarctic Peninsula; DP, Drake Passage; DML, Dronning Maud Land; EAIS, East Antarctic Ice Sheet; KP, Kerguelen Plateau; PB, Prydz Bay; RS, Ross Sea; TAM, Transantarctic Mountains; WAIS, West Antarctic Ice Sheet; WL, Wilkes Land; WS, Weddell Sea.
material, in particular from calcitic bivalves, with the main goal of improving age control of the core, and providing insight on marine climate at the time of carbonate precipitation. In addition, preliminary oxygen-isotope determinations in calcite samples seem to confirm contrasting marine climate conditions between the late Early Miocene (16.5–16.0 Ma), and the early Late Miocene (~ 11 Ma). In spite of the importance of windblown sediments for sea floor sedimentation and polar ocean biogenic productivity, the actual flux of such material blown onto the sea-ice is poorly documented. The paper by Atkins and Dunbar (2009-this issue) describes the mass flux and particle size distribution of aeolian sediment accumulating on sea-ice in Southern McMurdo Sound in the vicinity of the AND-2A drill site. Aeolian sediment was collected in November 2007, using three large sampling grids. These results reveal a surprisingly large volume of aeolian sediment (between 7.8 and 24.0 tonnes of aeolian sediment per km2). These data, combined with meteorological and satellite images indicate that a considerable amount of fine sand and dust is blown from the McMurdo Ice Shelf “dirty ice” northwards onto annual sea-ice.
The AND-2A drill site is located in one of the largest areas of exposed Cenozoic volcanic rocks in Antarctica, with an extended Miocene to present eruptive record of activity, coming from large volcanoes, as well as many smaller volcanic centres and volcanic fields of the Erebus Volcanic Province (e.g. Kyle, 1990). Del Carlo et al. (2009-this issue) report results from the study of the uppermost 37 m of the AND-2A drill core, corresponding to the most volcanogenic lithostratigraphic unit within the core. The authors present data on the age, composition, volcanological and depositional features of the volcanic sedimentary and tephra deposits of this unit and discuss their source, mechanisms of emplacement, and environment of deposition. The paper by Weigelt et al. (2009-this issue) reports on an interpretation of new high-resolution multichannel seismic reflection data, in order to reconstruct climate-related Late Cenozoic ice sheet variations on the shelf in the western Amundsen Sea Embayment (West Antarctica). The most interesting features on the seismic profiles are observed on the middle part of the shelf. Here, the distinct changes in reflection character indicate changes in depositional conditions due to repeated episodes of ice sheet extension in the
Author's personal copy F. Florindo et al. / Global and Planetary Change 69 (2009) v–vii
Amundsen Sea Embayment that are related to Late Cenozoic climate changes. Escutia et al. (2009-this issue) describe a multi-proxy approach to examine sediments recovered in drill holes from the West Antarctic Peninsula (ODP Leg 178, sites 1095 and 1096) and the East Antarctic Prydz Bay (ODP Leg 188, site 1165) margins, focusing on the climatic record between 4 and 3.5 Ma. According to the IPCC 2007 report, this time interval is extremely important, because the level of warming during the early-middle Pliocene is within the range of estimates of projected increases in the Earth's global temperature for the 21st century. The authors report evidence of warm conditions in both East and West Antarctica that correspond to periods of prolonged or extreme warmth correlated with marine oxygen-isotope stages Gi5, Gi1, MG11 and MG7. These results indicate coeval open marine conditions with warm summer sea surface temperatures (SSSTs), reduced sea-ice and significant reduction of both the Antarctic Peninsula Ice Sheet and the East Antarctic Ice Sheet during warm periods of the early and middle Pliocene. Acknowledgements We are grateful to our many colleagues for advice and encouragement through the production of this special issue. We gratefully acknowledge all the reviewers for their valuable criticism, comments and suggestions that substantially improved the quality of these contributions. We thank Femke Wallien, Tonny Smit and Herman Engelen of Elsevier Science for their support in the production of this special issue. The special issue would not have become reality without them. Finally, we would dedicate this special issue to the memory of our friend and Antarctic colleague Detlef “Dietz” Warnke, Geology professor at California State University—East Bay, who passed away on October 24, 2008. References Atkins, C.B., Dunbar, G.B., 2009. Aeolian sediment flux from sea ice into Southern McMurdo Sound, Antarctica. Global and Planetary Change 69, 133–141 (this issue). Barrett, P.J., Florindo, F., Cooper, A.K. (Eds.), 2006. Cenozoic paleoenvironments: geologic record and models: Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 231. 252 pp. Del Carlo, P., Panter, K.S., Bassett, K., Bracciali, L., Di Vincenzo, G., Rocchi, S., 2009. The upper lithostratigraphic unit of ANDRILL AND-2A core (Southern McMurdo Sound, Antarctica): local Pleistocene volcanic sources, paleoenvironmental implications and subsidence in the southern Victoria Land Basin. Global and Planetary Change 69, 142–161 (this issue). Dunbar, G.B., Bertler, N.A.N., McKay, R.M., 2009. Sediment flux through the McMurdo Ice Shelf in Windless Bight, Antarctica. Global and Planetary Change 69, 87–93 (this issue). Escutia, C., Bárcena, M.A., Lucchi, R.G., Romero, O., Ballegeer, A.M., Gonzalez, J.J., Harwood, D.M., 2009. Circum-Antarctic warming events between 4 and 3.5 Ma recorded in marine sediments from the Prydz Bay (ODP Leg 188) and the Antarctic
vii
Peninsula (ODP Leg 178) margins. Global and Planetary Change 69, 170–184 (this issue). Florindo, F., Cooper, A.K., O'Brien, P.E. (Eds.), 2003. Antarctic Cenozoic palaeoenvironments; geologic record and models. Palaeogeography, Palaeoclimatology, Palaeoecology 198, 278 pp. Florindo, F., Harwood, D.M., Wilson, G.S. (Eds.), 2005. Long term changes in southern high-latitude ice sheets and climate, the Cenozoic history. Global and Planetary Change 45 (1–3), 260 pp. Florindo, F., Nelson, A.E., Haywood, A.M. (Eds.), 2008. Antarctic cryosphere and Southern Ocean climate evolution (Cenozoic–Holocene). Palaeogeography, Palaeoclimatology, Palaeoecology, 260, 298 pp. Florindo, F., Siegert, M., 2009. Antarctic Climate Evolution. Developments in Earth and Environmental Sciences series, vol. 8. Elsevier, 593 pp. Giorgetti, G., Talarico, F., Sandroni, S., Zeoli, A., 2009. Provenance of Pleistocene sediments in the ANDRILL AND-1B drillcore: clay and heavy mineral data. Global and Planetary Change 69, 94–102 (this issue). Harwood, D., Florindo, F., Talarico, F., Levy, R., Kuhn, G., Naish, T., Niessen, F., Powell, R., Pyne, A., Wilson, G., 2009. Antarctic drilling recovers stratigraphic records from the continental margin. Eos 90 (11)10.1029/2009EO110002. IPCC, 2007. In: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., Miller, H.L. (Eds.), Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK. 996 pp. Kyle, P.R., 1990. McMurdo Volcanic Group: Western Ross Embayment. In: LeMasurier, W.E., Thomson, J.W. (Eds.), Volcanoes of the Antarctic Plate & Southern Oceans: AGU Antarctic Research Series, vol. 48, pp. 19–25. Washington. Marcano, M.C., Mukasa, S., Lohmann, K.C., Stefano, C., Taviani, M., Andronikov, A., 2009. Mass balance and mineralogical analysis of flotation plant survey samples to improve plant metallurgy. Global and Planetary Change 69, 124–132 (this issue). Naish, T., Powell, R., Levy, R., Florindo, F., Harwood, D., Kuhn, G., Niessen, F., Talarico, F., Wilson, G., 2007. A record of Antarctic climate and ice sheet history recovered. Eos 88 (50), 557–568 11 December 2007. Talarico, F.M., Sandroni, S., 2009. Provenance signatures of the Antarctic Ice Sheets in the Ross Embayment during the Late Miocene to Early Pliocene: the ANDRILL AND1B core record. Global and Planetary Change. 69, 103–123 (this issue). Weigelt, E., Gohl, K., Uenzelmann-Neben, G., Larter, R.D., 2009. Mass balance and mineralogical analysis of flotation plant survey samples to improve plant metallurgy. Global and Planetary Change 69, 162–169 (this issue).
Fabio Florindo Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy Corresponding author. E-mail address: fabio.fl
[email protected]. David M. Harwood Department of Geosciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0340, USA Richard H. Levy GNS Science, 1 Fairway Drive, Avalon, PO Box 30368, Lower Hutt 5040, New Zealand
