Jurassic biostratigraphy and paleoenvironmental evolution of the Malaguide complex from Sierra Espuña (Internal Betic Zone, SE Spain)

Geobios 39 (2006) 25–42 http://france.elsevier.com/direct/GEOBIO/

Jurassic biostratigraphy and paleoenvironmental evolution of the Malaguide complex from Sierra Espuña (Internal Betic Zone, SE Spain) Biostratigraphie du Jurassique et évolution paléoenvironnementale du complexe Malaguide de la Sierra Espuña (Zone bétique interne, SE de l’Espagne) Jesús E. Caracuel a,*, José Sandoval b, Manuel Martín-Martín a, Antonio Estévez-Rubio a, Iván Martín-Rojas a a

Departamento Ciencias de la Tierra y del Medio Ambiente, Universidad Alicante, Apdo 99, 03080 San Vicente del Raspeig, Alicante, Spain b Departamento Estratigrafía y Paleontología, Universidad Granada, Avenida Fuentenueva s/n, 18002 Granada, Spain Received 22 December 2003; accepted 28 September 2004 Available online 09 November 2005

Abstract Jurassic studies in the Internal Zones of the Betic Cordillera are scarce since this zone is composed mainly of pre-Jurassic metamorphic rocks. Only the “Dorsal” and the Malaguide domains include fossiliferous Jurassic successions, as in Sierra Espuña (SE Spain), which is one of the bigger and well-exposed Jurassic outcrops of the Internal Zones. Collected Ammonite assemblages update and improve the precision of previous biostratigraphic data by the recognition of: the Domerian (= Upper Pliensbachian, in the Mediterranean Domain) Lavinianum (Cornacaldense Subzone), Algovianum (Ragazzoni, Bertrandi, Accuratum and Levidorsatum Subzones) and Emaciatum (Solare and Elisa Subzones) Zones; the Lower Toarcian Polymorphum and Serpentinum Zones; the Middle Toarcian, Bifrons and Gradata Zone; the Upper Toarcian Reynesi Zone; the Lower/Upper Bajocian, the Lower Callovian Bullatus and Gracilis Zones; the Middle/Upper Oxfordian Transversarium, Bifurcatus, Bimammatum and Planula Zones; and the Lower and Upper Kimmeridgian Platynota, Strombecki, Divisum and Beckeri Zones. The paleoenvironmental evolution of the Malaguide Jurassic at Sierra Espuña shows similarities with other Mediterranean Tethyan paleomargins. The biostratigraphic precision along with the litho- and biofacies analyses has enabled the interpretation that the Malaguide paleomargin evolved as a passive margin, developing shallow carbonate platforms, until the Domerian (Lavinianum Zone). Then, the platform broke up (Domerian, Lavinianum Zone–Upper Toarcian, Reynesi Zone) with the beginning of the rifting stage, beginning the development of horst–graben systems and the coeval drowning of the area. This stage ended in the upper Lower Callovian (Gracilis Zone) to the Middle Oxfordian (Transversarium Zone) interval, starting the drifting stage, which accentuated the horst–graben systems, leading to the deposition of condensed nodular limestones in the raised sea bottom. © 2005 Elsevier SAS. All rights reserved. Résumé Les études sur le Jurassique des Zones Internes de la Cordillère bétique sont très peu abondantes du fait que les Zones Internes sont essentiellement composées de roches métamorphiques plus anciennes. Seuls, la Dorsale bétique et le Domaine Malaguide, où les roches sont en général épargnées par le métamorphisme, comprennent des successions fossilifères jurassiques d’intérêt biostratigraphique. C’est le cas de la Sierra Espuña où on peut observer un des affleurements les plus complets et mieux exposés des Zones Internes. Les associations d’ammonites permettent d’améliorer et de préciser les données biostratigraphiques préalables. Nous avons reconnu les Zones à Lavinianum (sous-zone à

* Corresponding author. E-mail address: [email protected] (J.E. Caracuel). 0016-6995/$ - see front matter © 2005 Elsevier SAS. All rights reserved. doi:10.1016/j.geobios.2004.09.002

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Cornacaldense), Algovianum (sous-zones à Ragazzoni, Bertrandi, Accuratum et Levidorsatum) et Emaciatum (sous-zones à Solare et Elisa) dans le Domérien; les zones à Polymorphum et Serpentinum dans le Toarcien inférieur ; les Zones à Bifrons et Gradata dans le Toarcien moyen et la Zone à Reynesi dans le Toarcien supérieur ; la partie supérieur du Bajocien inférieur et le Bajocien supérieur ; le Callovien inférieur, Zones à Bullatus et Gracilis ; les Zones à Transversarium, Bifurcatus, Bimammatum et Planula dans l’Oxfordien moyen/supérieur et les Zones à Platynota, Strombecki, Divisum et Beckeri dans le Kimméridgien. L’évolution de l’environnement du Jurassique Malaguide dans la Sierra Espuña montre beaucoup d’affinités avec les autres paléomarges de la Téthys méditerranéenne. La précision biostratigraphique et l’analyse des lithofaciès et des biofaciès nous ont permis d’interpréter la paléomarge Malaguide comme une paléomarge passive, avec le développement d’une plate-forme carbonatée sommaire jusqu’au Domérien (Zone à Lavinianum). Ensuite eut lieu la fracturation de cette plate-forme (Domérien inférieur, Zone à Levinianum-Toarcien supérieur, Zone à Reynesi) liée au commencement de la phase de « rifting », caractérisée par le développement d’un système de horsts et grabens et l’enfoncement de cette région. L’extension se poursuit entre le Callovien inférieur (Zone à Gracilis) et l’Oxfordien Moyen (Zone à Transversarium), en indiquant le début d’une phase de « drifting » qui aurait déclenché la réactivation du système de horsts et grabens, conduisant au dépôt de calcaires nodulaires condensés dans les parties les plus élevées du fond marin. © 2005 Elsevier SAS. All rights reserved. Keywords: Jurassic; Ammonite biostratigraphy; Paleoenvironmental evolution; Internal Betic Zone; Malaguide Complex; Southeastern Spain Mots clés : Jurassique ; Biostratigraphie des ammonites ; Évolution de l’environnement ; Zone Interne Bétique ; Complexe Malaguide ; Sud-Est de l’Espagne

1. Introduction The Jurassic evolution of the Betic Cordillera took place under distensive tectonic conditions related to Tethyan rifting. Although, the rifting age has been considered quite similar throughout the cordillera, controversy continues concerning the synchronism versus diachronism for the pre-, synand postrifting periods in the different domains into which the Betic Cordillera has traditionally been divided: the Internal and the External Zones. The External Zones belong to the South Iberian Paleomargin and consist of post-Triassic unmetamorphosed rocks. Thus, the Jurassic paleogeographic evolution and the age of the onset of the rifting (Carixian = Lower Pliensbachian), and the post-rifting phase (boundary Middle/Upper Jurassic) has been well-characterized (Vera, 1988). On the contrary, the Internal Betic Zones belong to a microplate (Mesomediterranean Terrain, Guerrera et al., 1993) derived from the North African continental margin, which collided against the External Zones during the Early Miocene. These zones are built up by the stacking of four complexes (in order upwards): Nevadofilabride, Alpujarride, Malaguide and “Dorsal”. The Nevadofilabride and Alpujarride are composed mainly of Paleozoic and Triassic (and older), metamorphic rocks, while the Malaguide and “Dorsal” Complexes include unmetamorphosed Paleozoic (Malaguide) and Meso-Cenozoic (Malaguide and “Dorsal”) sedimentary rocks. In general, the scarcity of Jurassic unmetamorphosed successions, together with the intense tectonic activity, have hampered the dating of the main Jurassic events in the Internal Zones. The Malaguide is the uppermost Complex (and, consequently, the most internal) of the Internal Zones, which outcrops mainly from Malaga Province (westward) to Murcia Province (eastward). In contrast to the other complexes, the Malaguide Complex includes Jurassic sedimentary covers, favoring the analysis of the Jurassic evolution of the Internal Betic Zones. The Sierra Espuña area, in Murcia Province, is

probably the most extensive, and the best exposed Jurassic outcrop belonging to the Malaguide in the Betic Cordillera. Except for the pioneer work by Fallot (1945), the main papers on the Jurassic of Sierra Espuña are from the 1960s and 1970s (Peyre and Peyre, 1960; Mac Gillavry et al., 1963; Navarro and Trigueros, 1963; Paquet, 1962, 1969; Geyer and Hinkelbein, 1971, 1974; Kampchuur et al., 1974; Seyfried, 1978, among others). Almost no recent studies have been made on the biostratigraphy and the paleogeographic evolution of the Jurassic of Sierra Espuña. In the present work, we analyze some classical Jurassic sections, together with new sections, in order to update the biostratigraphic framework and to approach the paleoenvironmental evolution of the Jurassic Malaguide from Sierra Espuña. Moreover, this will improve the knowledge of the Jurassic of the Internal Betic Zones, in addition to providing a fuller understanding of the External Betic Zones, and their relationships.

2. Geographical and geological setting The Sierra Espuña area is located in Murcia Province, accessible by road from the villages of Alhama and Totana, from the south, and Mula from the north (Fig. 1). The Malaguide outcropping area of Sierra Espuña bounds tectonically with the Alpujarride Complex to the SE, and with the External Betic Zones (Subbetic) to the NW. Laterally, the nearest outcrop of Jurassic Malaguide in the region is located 40 km westward, near Vélez Rubio in the Province of Almeria (Castillón Fm., Geel, 1973). The outcropping Malaguide Complex in Sierra Espuña is composed of two tectonic units (Martín-Martín, 1996); Morrón de Totana and Perona (Fig. 1). The Morrón de Totana Unit is the footwall while the Perona Unit is the hanging wall, which, paleogeographically came from a more proximal position (Martín-Martín and Martín-Algarra, 1997). Both units include a marine Jurassic sedimentary cover, although in the

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Fig. 1. Geographical (upper) and Geological (lower) sketches with the location of the 5 studied sections at Sierra Espuña. Legend: 1. Undifferentiated Quaternary. 2. Eocene platform carbonates. 3. Lower Cretaceous marls and marly limestones. 4. Upper Jurassic marl, limestones and nodular limestones. 5. Domerian– Lower Callovian cherty rhythmic limestones. 6. Liassic p.p. shallow water limestones. 7. Triassic/Liassic? Dolostones. 8. Triassic conglomerates and sandstones. Fig. 1. Croquis géographique (supérieur) et géologique (inférieur) avec l’emplacement des 5 sections étudiées dans la Sierra Espuña. Légende : 1. Quaternaire indifférencié. 2. Plate-forme carbonatée éocène. 3. Marnes et calcaires marneux du Crétacé inférieur. 4. Marnes, calcaires et calcaires noduleux du Jurassique supérieur. 5. Calcaires rythmiques à silex du Domérien inférieur - Callovien. 6. Calcaires d’eaux peu profondes du Lias p.p. 7. Dolomies du Trias/Lias?. 8. Conglomérats et sables du Trias.

Perona Unit only outcrops Liassic sediments and have a reduced areal extension. In this unit, only one section was selected for studying (Perona section; Fig. 1). In the Morrón de Totana Unit, the Jurassic is well developed, outcropping with lateral continuity along more than 12 km (Fig. 1). Here, four sections were analyzed, these being spaced 2–5 km from each other in an E-W direction (Malvariche, Tres Carrascas, Prat Mayor and Morrón Chico sections; Fig. 1).

3. State-of-the-art Jurassic Malaguide at Sierra Espuña The first relevant data on the Jurassic from Sierra Espuña come from Fallot (1929, 1945), who studied the Jurassic successions at Morrón Chico and Prat Mayor. This author recognized, within the carbonate succession of the platform, a ferruginous oolith-rich interval (0.5–3 m thick) with late Liassic ammonites (Dumortieria sp. and Pleydellia sp.). This

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guide-level was first noted by Villasante (1912), who assigned it a Lusitanian to Kimmeridgian age. Later on, Peyre and Peyre (1960) and Navarro and Trigueros (1963) fixed the age of the ferruginous oolith-rich interval studied by Fallot (1945), based on the faunas (ammonites and brachiopods) collected in the Prat Mayor section. Peyre and Peyre (1960) recognized abundant ammonites of the genera Lytoceras, Coeloceras, Reynesoceras, Arieticeras, Harpoceras and Protogrammoceras, and brachiopods (Spiriferina, Terebratula and Rhynchonella), and used them to date the Middle Domerian (Domerian = Upper Pliensbachian, in the Mediterranean Domain). No more macrofauna was collected in the remaining Jurassic succession, although the record of microfacies enriched in crinoids, foraminifers (Involutina, Nodosaria and Lenticulina), Stomiosphaera and Cadosina toward the upper part, make feasible to assume the existence of the Middle and Upper Jurassic, as in the section at Morrón Chico studied by Fallot (1945). The synthesis by Paquet (1969), and precursor works (Paquet, 1962), are the most exhaustive studies of the Jurassic from Sierra Espuña, including the analysis of sections in the Morrón de Totana and Perona tectonic units. According to Peyre and Peyre (1960) and Paquet (1969) proposed a Middle Domerian (Upper Pliensbachian) age for the ferruginous oolith-rich level of the Liassic in the Prat Mayor section, based on the record of Fuciniceras cf. curionii (Meneghini), Protogrammoceras bassanii (Fucini), Arieticeras bertrandi (Kilian) and Ar. fuccinii (Del Campana), among others. In the Perona section, the same level was dated by Paquet, using brachiopods as Lower Pliensbachian, leading to the suggestion that the ferruginous oolith-rich interval might be diachronous. According to Paquet (1969), the Lower/Middle Jurassic boundary in the Morrón de Totana Unit (probably studied in the Prat Mayor section), begins with a thick oolitic-limestone level (25 m) with gastropods and bivalve fragments, evolving to whitish-gray micritic limestones with filaments (10 m), and later on, well-bedded gray, slightly marly, pelagic limestones (25 m) with “Cancellophycus”, filaments, and Globochaete alpina Lombard belonging to the Middle Jurassic. In the Upper Jurassic analyzed in the same localities, including the Fuente Blanca section (here called Prat Mayor), Paquet (1969) recognized well-bedded gray limestones with filaments at the base, slightly marly limestones with Globochaete above and grayish-white, more or less nodular, limestones with Calpionella alpina Lorenz, Stomiosphera minutissima (Colom), G. alpina Lombard, Textulariidae and Lageniidae towards the upper part. Geyer and Hinkelbein (1971, 1974) focused on the detailed biostratigraphy of the Liassic ferruginous oolith-rich interval, outcropping in the Morrón de Totana (Morrón de Alhama section, for these authors) and Prat Mayor (Fuente Blanca section, for these authors). Geyer and Hinkelbein (1971, 1974) made a detailed correlation of this 5 m thick section, dating it as the Upper Pliensbachian (on the basis of a few and badly preserved forms of Arieticeras/Canavaria/Fontanelliceras,

Lioceratoides and Catacoeloceras) in the lower part of Prat Mayor section. In the upper part of Morrón de Totana section, it was dated as the Middle Toarcian [Peronoceras cf. millarense Monestier, Catacoeloceras tethysi Géczy, Hildoceras cf. graecum Renz, Hi. cf. bifrons (Bruguière), among others], and the Upper Toarcian [Hugia cf. variabilis (d’Orbigny), Grammoceras thouarsense (d’Orbigny), Dumortieria sp. and Pleydellia sp., as more relevant]. Thus, these authors assumed an Upper Pliensbachian–Aalenian? age for the complete interval in both sections, avoiding the interpretation of the diachroneity proposed by Paquet (1962, 1969). Kampchuur et al. (1974) assigned 90 m of white oolitic limestones with algae (Thaumatoporella), ostracods, and foraminifers to the pre-Domerian Liassic. Over these shallow platform carbonates appear a few meters of ferruginous oolithrich limestones. These authors accepted the dating by Paquet (1969) for this guide horizon as Middle Domerian in the Morrón de Totana Unit, and then the subsequent diachrony of such level. The Dogger encompasses 100–140 m thick of oolitic limestones with crinoids, miliolids and ostracods, evolving to biopelmicrites, rich in echinoderms, “filaments”, Ammodiscus, and lagenids. The Upper Jurassic is composed of 90 m of massive limestones, occasionally nodular, with radiolaria, Globuligerina, G. alpina Lombard, and ostracods, with Saccocoma and calpionellids in its upper part. Seyfried (1978) studied some Jurassic sections at Casas y Pozos de Murcia (equivalent, in part to the Prat Mayor and Tres Carrascas sections here) recognizing the ferruginous oolith-rich level with abundant Middle Domerian faunas. The Middle Jurassic materials are represented by 65–70 m of oolitic/crinoidal limestones, and gray laminated limestones containing trace fossils, interbedded with turbiditic levels with resedimented oolites and scarce Upper Bajocian ammonites (Spiroceras sp., Nannolytoceras sp.). The overlying Upper Jurassic (approximately 45 m thick) includes calcareous breccias, pelites and fluxoturbidites with foraminifers, bivalves (Inoceramus) and Oxfordian ammonites (Phylloceras sp., Holcophylloceras sp., Sowerbyceras sp., Arisphinctes sp. and Dichotomosphinctes? sp.) at its base, with massive limestones above and well bedded limestones (pelmicrosparite and biopelmicrite) with foraminifers, crinoids, and echinoids in its upper part. Recently, Caracuel et al. (2001) and Martín-Rojas et al. (2002) described the general stratigraphy of a new Jurassic section near Malvariche, where the lithofacies are similar to those of the classical outcrops at Prat Mayor and Morrón Chico. In the Malvariche section, these authors found ammonite assemblages indicating the Middle Domerian (Algovianum Zone; ferruginous oolith-rich limestones), the Lower Callovian [Bullatus and Gracilis (= Patina zone, sensu Sequeiros, 1974)], and the uppermost Kimmeridgian (Beckeri Zone). 4. The sections studied: stratigraphic data Five Jurassic sections were studied in Sierra Espuña; the three classical sections already mentioned from Fallot (1945)

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to Seyfried (1978); Prat Mayor, Morrón Chico and Perona, (Fig. 1), and two new ones (Malvariche and Tres Carrascas sections; Fig. 1). Sections were selected to cover the Morrón de Totana tectonic Unit (Malvariche, Tres Carrascas, Prat Mayor and Morrón Chico sections; Figs. 1–3) and the Perona Unit (Perona section; Figs. 1 and 3), evenly spaced along the Sierra Espuña. The present study was focused in the Prat Mayor and Malvariche sections (Fig. 2) since they are easily accessible, are little tectonized and contain the most complete, and fossilrich successions. In sections at Tres Carrascas, Morrón Chico and Perona, only the Liassic (especially the ferruginous oolithrich limestone interval) was studied. Along with the stratigraphical and sedimentological analysis, more than 140 thin sections were used for characterizing the microfacies, textures and microfossil content; particularly the Globuligerina and calpionellids, during the Upper Jurassic, which have potential biostratigraphic interest. Macroinvertebrates (more than 500 specimens), mainly ammonites and brachiopods, were sampled in favorable facies for biostratigraphy. 4.1. Lower Jurassic The Lower Jurassic was analyzed in all sections studied. It is composed of oo-oncolitic limestones, sometimes brecciated, evolving to crinoidal limestones, with an interval of ferruginous silty limestones at the top. In the Malvariche and Prat Mayor sections, the lower boundary is better exposed and makes contact tectonically with massive saccaroid dolostones, sometimes attributed to the earliest Jurassic. The thickness of the outcropping Lower Jurassic, which sometimes can be slightly dolomitized at its base, ranges from 70 to 125 m. No dating was established for the oo-oncolitic limestones, but, in any case, an Early Jurassic age is ruled out by the presence of Lithiotis-rich levels, typical for the Liassic Perimediterranean Tethys. Moreover, Kampchuur et al. (1974) suggests a Sinemurian to Pliensbachian age for its microfauna. By contrast, the upper part with ferruginous silty limestones were easily dated in all sections, ranging from the Domerian (= Upper Pliensbachian; Lavinianum Zone, Cornacaldense Subzone) to the Upper Toarcian (Reynesi Zone), according to the ammonite assemblages collected. In all sections studied, the lower part of the succession is composed of oo-oncolitic, evolving to crinoidal limestones, showing decametric thickening and upwardly coarsening parasequences (10–25 m thick), quite stable both in thickness and lithofacies variation, with no evident stacking trend. The elementary parasequence appears to be built up by white oo-pisolitic limestones evolving to pinkish oncolitic–rodolitic limestones, sometimes breccioids, and topped by an algal crust and/or an intensely bioturbated/bored surface. Crossbedded grainstones are usual in the lower part of the parasequences. Microfacies are mainly grainstones to packstones (occasionally rudstones) with oolites, pisolites and/or oncolites and,

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secondarily, algae [Cayeuxia piae Frollo, Palaeodasycladus mediterraneus (Pia)], ostracods, sponges, and benthic foraminifers. Some levels are rich in Textulariidae, Siphovalvulina sp., and transitional forms of Mayncina termieri Hottinger and Lituosepta compressa Hottinger, which are characteristics of the protected Liassic platform of the Mediterranean (Sartorio and Venturini, 1988). Benthic macrofauna such as gastropods, bivalves (pectinids, ostreids and Lithiotis), brachiopods, solitary corals, echinoderms are often abundant (Fig. 2). Generally, they are found in living positions, as for example the characteristic Lithiotis horizon of the upper part of the elementary parasequences. The upper part of the Lower Jurassic succession is built up by 2–12 m of alternating yellowish marly/silty limestones, occasionally slightly nodular, with levels of ferruginous oolites and/or decimetric Fe–Mn oncoids, which are formed by concentric laminae around a nucleus (meter levels 110– 122 in Malvariche and 60–65 in Prat Mayor; Fig. 2). Only in section at Morrón Chico, does the base of this interval show a karst-like irregular surface sinking more than 2 m on the underlying crinoidal limestones. This characteristic interval, which can be used as a guide-horizon for geological mapping, is well-developed and widespread in Sierra Espuña. Some sections contain a similar interval made up of yellowish marly/silty limestones, although thinner, less continuous and fossiliferous (meter levels 88–92 in Malvariche and 20–25 in Prat Mayor; Fig. 2). In the five sections studied, the interval of ferruginous silty limestones with Fe-oolites is rich in well-preserved macrofauna with neomorphosed ammonite and brachiopod shells, together with oriented belemnites, bivalves, gastropods, and echinoderms (Fig. 3). Trace fossils (Thalassinoides, Planolites and Chondrites) are widespread in the marly levels. As shown in Fig. 3, the ammonites collected have enabled the characterization of discrete and discontinuous horizons within the Domerian (Lavinianum, Algovianum and Emaciatum Zones) and the Toarcian (Polymorphum, Serpentinum, Bifrons, Gradata and Reynesi Zones). 4.2. Middle Jurassic The studied Middle Jurassic sections at Malvariche and Prat Mayor are 138 and 145 m thick, respectively (Fig. 2). They are composed mainly of well-stratified micritic/crinoidal limestones with abundant chert in nodules and ribbons, increasing toward the upper part. At the base, the micritic/ crinoidal limestones alternate with thick oolitic limestones levels, which resemble that of the Lower Jurassic. Toward the upper part, some levels composed by micritic limestone show incipient nodularization, with abundant trace fossils (mainly Thalassinoides), developing two multiple hard grounds at the top, with an accumulation of glauconite or ferruginous crusts and faunal concentrations, including ammonites and occasionally oriented belemnites (“belemnite battlefields” sensu Doyle and MacDonald, 1993). As a whole, the lower and middle part of the Middle Jurassic is composed of upwardly thickening and coarsening

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parasequences (2–5 m thick), with stacking of upwardly thicker parasequences. Microfacies range from wackestones to packstones (occasionally crinoidal grainstones) with crinoids, along with thin-shelled bivalves (“filaments”), radiolaria, benthic and planktonic foraminifers, and other macroinvertebrate fragments. Apart from disarticulated crinoid ossicles, benthic macrofauna are almost absent in the Middle Jurassic, in contrast to the Lower Jurassic. Planktonic macrofauna is also scarce, but in the top of some levels, especially toward the upper part, cephalopods proved widespread (ammonites and belemnites). In these levels, better developed in the Malvariche section, ammonites assemblages were collected, enabling recognition of the Lower Bajocian, based on the record of a specimen of Skirroceras sp. Also recognized were the Lower Callovian [Bullatus Zone; based on the record of Homoeoplanulites sp., Macrocephalites sp., and Kheraiceras cf. bullatus (d’Orbigny)], and the Gracilis Zone (Patina Zone sensu Sequeiros, 1974) with abundant and significant ammonites, especially Macrocephalinae and Reineckeidae. No other ammonite faunas were found in the Middle Jurassic.

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upwardly thinning parasequences continues 15 m more over the encrinitic bank, and then change to upwardly thickening parasequences; the facies change gradually to alternating marly/calcareous nodular limestones, often brecciated. The upper 20 m are composed of crinoidal levels and marly intervals with microfacies enriched in hyaline calpionellids which characterized the Upper Tithonian. In the Prat Mayor section above the marly limestones with Globuligerina, outcrop 50 m of ammonitico rosso nodular limestones alternating with thick breccioids banks, organized in upwardly coarsening and thickening parasequences (2–4 m thick). In this interval, ammonite assemblages characterizing the Middle–Upper Oxfordian and the Lower– Middle? Kimmeridgian were collected. In contrast to the Malvariche section, no ammonites from the Upper Kimmeridgian were found. The upper part of section at Prat Mayor appears similar to Malvariche, although more reduced and with characteristic breccioid banks. In both sections, the calpionellids Zones of Chitinoidella, Crassicollaria and Calpionella were recorded.

4.3. Upper Jurassic 5. Ammonite biostratigraphy The Upper Jurassic features at Malvariche and Prat Mayor differ somewhat with regard to lithofacies and faunal assemblages, although the thicknesses are quite similar, 80 and 90 m, respectively (Fig. 2). As a whole, the succession is composed by finely stratified marl and marly limestones which evolved to stratified limestones stacked in thickening upward parasequences (1–2 m thick). Then, massive nodular limestones (sometimes brecciated) alternate with stratified limestones and marls, arranged in upwardly thinning parasequences. Textures and microfacies are highly variable, ranging from pelloidal mudstones to intraclastic packstones (occasionally crinoidal grainstones) with Globuligerina (at the base), filaments, Saccocoma, radiolaria, Globochaete, Stomiosphaera, Cadosina, macroinvertebrate fragments (mainly ammonites and belemnites) and calpionellids (in the upper part). In both sections (Fig. 2), above the multiple Fe–Mn crusts dated as Lower Callovian (Gracilis Zone) outcrops a 5–10 m thick interval of marly limestones and marls, finely stratified, and texturally mudstones to wackestones rich in Globuligerina, attributed to the Callovian?–Oxfordian. In the Malvariche section, 7 m of slightly nodular marly limestones appear in upwardly thickening parasequences. Towards the top, there is an irregular massive breccioid bank, 4 m of slightly nodular marly limestones organized in upwardly thinning parasequences, and a characteristic crinoidal bank with an erosive base. Just below this crinoidal bank, ammonite assemblages were collected from the uppermost Kimmeridgian (Beckeri Zone). These slightly nodular marly limestones stacked in

Fig. 2. Correlation of the Jurassic sections at Malvariche and Prat Mayor. Fig. 2. Corrélation des sections jurassiques de Malvariche et Prat Mayor.

Jurassic ammonite faunas belonging to the Internal Zone of the Betic Cordillera has been rarely and discontinuously reported, and in all cases from the non-metamorphosed Malaguide and “Dorsal” domains (Fallot, 1929, 1931–1934, 1945; Peyre and Peyre, 1960; Azema, 1960, 1961; Paquet, 1969; Geyer and Hinkelbein, 1971, 1974; Seyfried, 1978 and Caracuel et al., 2001). Biostratigraphic data from Sierra Espuña come mainly from Geyer and Hinkelbein (1974); Seyfried (1978) and Caracuel et al. (2001), who described ammonite assemblages belonging to the Domerian, Middle–Upper Toarcian, Upper Bajocian, Oxfordian and Upper Kimmeridgian. For the present paper, more than 500 macroinvertebrates, mainly ammonites, were collected in order to complete and to revise the biostratigraphic framework from the Domerian to the Kimmeridgian in the three previously studied and two new Jurassic sections at Sierra Espuña. The ammonite zonal/subzonal scheme in Cariou and Hantzpergue (1997) for the Mediterranean Domain was used in the Domerian, Toarcian and Callovian stages. Domerian ammonites show good preservation with neomorphosed shells, sometimes ferruginous, and mostly with preserved living chambers; phragmocone septa are consistently preserved (Figs. 4 and 5). There appears to be no taphonomic size bias, although the smaller ammonoids (occasionally fragments) are sometimes found in the interior of Fe–Mn oncoids, with a variable mode of preservation.

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Fig. 3. Detailed successions in the five Domerian–Toarcian sections studied; interval of alternating yellowish marly/silty limestones, occasionally slightly nodular, with levels of ferruginous oolites and/or decimetric oncoids. Recognized Zones and Subzones (according to Cariou and Hantzpergue, 1997) are shaded in the chronostratigraphic chart. Legend as in Fig. 1. Fig. 3. Successions détaillées des cinq sections du Domérien–Toarcien étudiées ; intervalle d’alternance des calcaires marno-silteux jaunâtres, parfois légèrement noduleux, avec des niveaux décimétriques d’oncoïds et/ou d’oolites ferrugineuses. Les zones et sous-zones reconnues (d’après Cariou et Hantzpergue, 1997) sont ombragées sur le tableau chronostratigraphique. Légende, cf. Fig. 1.

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In the lower level of yellowish silty/limestones or silty/marly limestones of the Malvariche section (meter levels 88–92), which contains abundant bivalves, ammonite are scarce and fragmentary; we have recognized Lytoceras villae Meneghini, Fuciniceras gr. isseli (Fucini), Fu. cornacaldense (Taush) and Fieldingiceras fieldingii (Reynes), indicating that, at least in this section, the Lower Domerian (Lavinianum Zone, Cornacaldense Subzone) is represented in Sierra Espuña. In Malvariche (meters 110–122) and Prat Mayor (meters 60–65) the alternating yellowish marly/silty limestones, occasionally slightly nodular, with levels of ferruginous oolites and oncoids (Figs. 2 and 4), have supplied abundant, diversified and relatively well preserved ammonites: Ly. villae Meneghini (Fig. 4A), Fi. fieldingii (Reynes) (Fig. 4B), Fu. cornacaldense (Taush) (Fig. 4C), Protogrammoceras aequiondulatum (Bettoni), Pr. aff. ilurcense Braga, Arieticeras algovianum (Oppel) (Fig. 4E), Ar. disputabile (Fucini) (Fig. 4F), Ar. amalthei (Oppel), Ar. bertrandi (Kilian), Leptaleoceras accuratm (Fucini), Le. ugdulenai (Gemmellaro), Becheiceras bechei (Sowerby), Reynesoceras acanthoides (Reynes), Re. ragazzonii (Hauer) (Fig. 4D), and Parstchiceras aff. proclive (Rosemberg). According to Braga (1983), this ammonite assemblage dates the Middle Domerian (Algovianum Zone; Ragazzoni, Bertrandi and Accuratum Subzones) and possibly the Lower Domerian [Lavinianum Zone, as is shown the by the record of Fu. cornacaldense (Taush), Fi. Fieldingii (Reynes) and Be. Bechei (Sowerby)]. Although most of the ammonites are clearly reworked, it is possible that, with a detailed sampling, the three Middle Domerian Subzones could be separated, given that different samples (some with several ammonites species) can have different lithologies. In Tres Carrascas section, at 40 cm of the base (Fig. 3), we have recorded Emaciaticeras levidorsatum Fucini (Fig. 4H), Em. speciosum Fucini, Em. sp., and Dactyliocetatidae ind., which are representative of the upper Middle Domerian (Algovianum Zone; Levidorsatum Subzone). Also in this section, 60 cm upward (samples TC.100C) we have found Pleuroceras solare (Phillips), Em. sp., Lioceratoides fucinianus (Haas), Li. exapatus (Gemmellaro), and Neolioceratoides hoffmanni (Gemmellaro), which characterize the lower Upper Domerian (Emaciatum Zone, Solare Subzone). The samplings TC.100A and TC.100B, both in Tres Carrascas section (Fig. 3) contain Em. archimedis Fuccini, Em. lottii (Gemmellaro) (Fig. 4G), Em. timaei (Gemmellaro) (Fig. 4I), Em. sp., Li. serotinus (Bettoni), Li. micetoi (Fucini) and Ne. hoffmanni (Gemmellaro). This assemblage dates the uppermost Domerian (Emaciatum Zone, Elisa Subzone). Domerian/Toarcian transition has been recognized in the lower part of the Morrón Chico section (Fig. 3), with the following ammonite assemblage: Li. lorioli (Bettoni), Li. sp., Ne. hoffmanni (Gemmellaro) Ne. schopeni (Gemmellaro), Canavaria sp., Ca. gregalis Fucini and Fontanelliceras fontanellense (Gemmellaro). Braga (1983) proposed that this assemblage may correspond to the uppermost Domerian (Elisa Subzone)–lowermost Toarcian (Polymorphum Zone).

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As in the External Zones (Subbetic) of the Betic Cordillera (see Braga, 1983), the Hildoceratidae (Harpoceratinae and Hildoceratinae) and Lytoceratidae clearly dominate the Domerian ammonite assemblages, indicating its typical Mediterranean character. Dactylioceratinae are also abundant in the Ragazzoni Subzone, whereas other groups such as Phylloceratidae, Amaltheidae and Liparoceratidae, though also present, are scarce. Toarcian materials are clearly represented in the Perona Unit (Fig. 3) where some specimens of Dactylioceras (Eodactylites) sp. and Hildaites striatus Guex have been recorded, pointing to an Early Toarcian age (Polymorphum and Sepentinum Zones). Middle and Upper Toarcian sediments are well represented in the Morrón Chico section, where a minimum of four fossiliferous levels can be differentiated (Fig. 3). The lower one (40 cm upward of the base), reported above, represents the Domerian/Toarcian transition. The following fossiliferous level, located approximately 140 cm upward (samples MC.180), shows reduced net sedimentation with very thinly laminated Fe–Mn layers which encrust either the discontinuity surfaces or very well-preserved fossils, especially ammonites. The following ammonite species occur: Hildoceras bifrons (Brugière) (Fig. 4J), Hi. semipolitum Buckman, Pseudomercaticeras venzoi Pinna, Osperleioceras bicarinatum (Zieten), Phymatoceras (Furloceras) chelussi (Parisch and Viale) (Fig. 5A), Ph. (Fu.) venustulum (Merla), Mouterdeiceras sp., Catacoeloceras crassum (Young and Bird), Ca. sp., Platystrophites latusi Levi-Seti and Oxyparoniceras? sp. This ammonite assemblage represents the Middle Toarcian, Bifrons Zone (Bifrons Subzone) and possibly the base of the Gradata Zone. A single specimen of Mouterdeiceras sp. from 6.5 m from the base in the Morrón Chico section indicates the Gradata Zone. According to Geyer and Hinkelbein (1974), who reported Upper Toarcian ammonites from this section, some specimens of Geczyceras speciosum (Janensch) (Fig. 5B), Pseudogrammoceras sp. and Lytoceras sp. appear from approximately 3.5 m upward, which are indicative of the lower part of the Upper Toarcian, lower part of Reynesi Zone (Fig. 5). A single fragment of ex situ Dumortieria sp. indicates the upper part of the Reynesi Zone. Middle Jurassic ammonite assemblages were better registered in the Malvariche section. Just below the lower level of a multiple limonite crust (230 m in Fig. 2) we sampled scarce and badly preserved fauna (Skirroceras sp.), which can be attributed to the upper Lower Bajocian. The upper levels of these crusts have provided articulated crinoids, oriented belemnites, and some deformed specimens of Homoeoplanulites sp., Macrocephalites sp., Kheraiceras cf. bullatus (Orbigny) and Kh. (Bomburites) sp. from the Lower Callovian (Bullatus Zone). Some meters upward, also in the Malvariche section, ammonite assemblages were collected from the Lower Callovian (Gracilis Zone = Patina Zone, sensu Sequeiros, 1974). These show taphonomic reworking with neomorphized shells

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Fig. 4. Lower Jurassic ammonites from Sierra Espuña. All the specimens are figured at natural size except for B (× 2). A. L. villae Meneghini, MI.121S.1, Middle Domerian, Algovianum Zone, Malvariche section 121 m. B. F. fieldingii (Reynes), MI121S.2, Middle Domerian, Malvariche section 121 m. C. Fuciniceras cornacaldense (Taush) MI.121S.3, Malvariche section 121 m, D. Reynesoceras ragazzonii (Hauer), MI.121S.4, Middle Domerian, Algovianum Zone, Malvariche 121.5 m. E. A. algovianum (Oppel), MI.121S.5, Algovianum Zone, Malvariche section 121.5 m. F. Arieticeras disputabile (Fucini), PM.60.10,

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together with inner molds, sometimes truncated, corroded, occasionally fragmented, and usually imbricate. Both inner molds and shells can occasionally be covered by Fe–Mn crusts. The assemblage is dominated by Phylloceratina [Phylloceras trifoliatum Neumayr, Holcophylloceras zignodianum (Orbigny), Calliphylloceras disputabile (Zittel) and Ptychophylloceras flabellatum (Neumayr)], which reach the 60%. Macrocephallitinae as Macrocephalites gracilis (Spath) (Fig. 5E), and Macrocephalites? sp. along with Haploceratidae [Lissoceratoides jullieni (Douvillé)] are also abundant. Other groups as Hecticoceratinae (Hecticoceras (Chanasia) bannense Elmi (Fig. 5C) , He. (Ch.) sp. and Jeanneticeras? sp.), Reineckeiidae [Rehmannia (Re.) freii (Jeannet) sensu Cariou (1980) (Fig. 5D), Collotia oxyptycha (Neumayr)], Perisphinctidae (Choffatia waageni (Teisseyre), Grossouvria sp., Parapatoceratinae, (Parapatoceras tuberculatum (Baugier and Sauzé), Pa. sp.) and Oppeliinae (Oxycerites sp.) are also common. Middle Jurassic ammonites are scarcer in Prat Mayor section. Seyfried (1978) reported Spiroceras sp. and Nannolytoceras sp. from the Upper Bajocian, and we collected only two specimens (Hecticoceras (Ch.) sp. and Grossouvria sp., 214 m) which probably represent the Lower Callovian (Gracilis Zone). Oxfordian ammonite assemblages were recorded in 7 m of succession in the Prat Mayor section (237.5–244.5 m in Fig. 2) at the top of nodular-limestone levels, sometimes brecciated. As usual in ammonitico rosso facies, ammonites are preserved as inner moulds with complete phragmocone and incomplete body chambers. Sutures are poorly or not at all preserved, indicative of relatively deep deposition (FernándezLópez, 2000). No significant taphonomic size bias was noted, although the smaller ammonites are frequently lying oblique (even vertical) with respect to the stratification, especially at the top of the strata. As a whole, Phylloceratina reach the 37.5% (mainly Calliphylloceras and secondarily Sowerbyceras) of the assemblage. The Middle Oxfordian, Transversarium Zone, was registered in a single horizon with the record of Calliphylloceras silesiacum (Oppel), Ca. manfredi (Oppel), Sowerbyceras tortisulcatum (d’Orbigny), Euaspidoceras (Eu.) gr. oegir (Oppel), Taramelliceras (Ta.) cf. callicerum (Oppel), Perisphinctes (Arisphinctes) cf. helenae De Riaz and Pe. (Dichotomosphinctes) sp., among others. Some 2 m upward, there are three horizons with scarce but significant fauna of

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Pe. (Dichotomoceras) bifurcatoides Enay (Fig. 6A), Pe. (Di.) cf. bifurcatus (Quenstedt), Pe. (Dichotomosphinctes) cf. elisabethae (De Riaz) and a specimen of Pe. (Dichotomosphinctes) aff. ultimus, with atypical abundance of trifurcate ribs in the body chamber, together with Calliphylloceras and Sowerbyceras, which characterize the Bifurcatus Zone. The Upper Oxfordian, Bimammatum Zone (or still the uppermost Bifurcatus Zone) was unsurely recorded in a horizon with Passendorferia (Passendorferia) cf. teresiformis (BrochwichLewinski), Pa. (Pa.) sp. and Trimarginites gr. trimarginatus Oppel, just 50 cm below the first record of Subnebrodites in the Planula Zone. Upwardly, four ammonite-bearing horizons, spaced within a thickness of 2.5 m, enabled the recognition of the Planula Zone by the record of Subnebrodites cf. schröederi (Wegele), Su. cf. minutum (Hehl) sensu Zieten (1830–1834), Passendorferia (Pa.) aff. uptonoides (Fig. 6B), Pa. (Pa.) sp., Physodoceras altenense (d’Orbigny), Orthosphinctes sp. and abundant Phylloceratina (mainly Sowerbyceras). Kimmeridgian ammonite assemblages in the Prat Mayor section were registered from 246.4 to 260 m (Figs. 2 and 6). As in the underlying Oxfordian, the lithofacies is composed by nodular limestones with thicker and more brecciated levels. The Kimmeridgian succession has less, and more widely spaced, ammonite-bearing horizons. Nevertheless, the ammonite mode of preservation is similar to that of the Oxfordian, although, due to the higher sedimentation rate, some specimens have lost the inner whorls (or have become flattened due to the absence of sediment infill during early diagenesis). The amount of Phylloceratina is higher, reaching the 50%, mainly by the contribution of the eurythopic genus Sowerbyceras. Almost 2 m above the last record of the Planula Zone, there is a horizon attributed to the lowermost Kimmeridgian (Platynota Zone?) based on the record of Sutneria gr. galar (Oppel), Streblites tenuilobatus (Oppel), Glochiceras (Lingulaticeras) gr. nudatum (Oppel)-lingulatum (Quenstedt), Gl. (Li.) sp., Aspidoceras sp., Orthosphinctes (Orthosphinctes) polygyratus (Reinecke) sensu Schairer morph. colubrinus Olóriz (Fig. 6F), Or. (Or.) sp, Or. (Lithacosphinctes) sp. and abundant Phylloceratina [So. silenum (Fontannes) as well as, secondarily, Ly. orsinii (Gemmelaro) and Ho. mediterraneum (Neumayr)]. Above appear Nebrodites (Nebrodites) gr. hospes (Neumayr) (Fig. 6C), Ne. (Ne.) sp., Presimoceras sp.,

Middle Domerian, Algovianum Zone, Prat Mayor section 60 m. G. Emaciaticeras lottii Fucini, TC.100A.3, Upper Domerian, Emaciatum Zone, Tres Carrascas section 1 m. H. E. levidorsatum Fucini, TC.40.1 Upper Domerian, Emaciatum Zone, Tres Carrascas section 0.4 m. I. Emaciaticeras timaei (Gemmellaro), TC.100A.2, Upper Domerian, Emaciatum Zone, Tres Carrascas section 1 m. J. H. bifrons (Brugière), MC.180.1, Middle Toarcian, Bifrons Zone, Morrón Chico section 1.8 m. Fig. 4. Ammonites du Jurassique inférieur de la Sierra Espuña. Tous les spécimens sont représentés à grandeur naturelle sauf B (× 2). A. L. villae Meneghini, MI.121S.1, Domérien moyen, Zone à Algovianum, section de Malvariche 121 m. B. F. fieldingii (Reynes), MI121S.2, Domérien moyen, section de Malvariche 121 m. C. Fuciniceras cornacaldense (Taush) MI.121S.3, section de Malvariche 121 m. D. Reynesoceras ragazzonii (Hauer), MI.121S.4, Domérien moyen, Zone à Algovianum, section de Malvariche 121,5 m. E. A. algovianum (Oppel), MI.121S.5, Zone à Algovianum, section de Malvariche 121,5 m. F. Arieticeras disputabile (Fucini), PM.60.10, Domérien moyen, Zone à Algovianum, section de Prat Mayor 60 m. G. Emaciaticeras lottii Fucini, TC.100A.3, Domérien supérieur, Zone à Emaciatum, section de Tres Carrascas 1 m. H. E. levidorsatum Fucini, TC.40.1, Domérien supérieur, Zone à Emaciatum, section de Tres Carrascas 0,4 m. I. Emaciaticeras timaei (Gemmellaro), TC.100A.2, Domérien supérieur, Zone à Emaciatum, section de Tres Carrascas 1 m. J. H. bifrons (Brugière), MC.180.1, Toarcien moyen, Zone à Bifrons, section de Morrón Chico 1,8 m.

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Fig. 5. Lower and Middle Jurassic ammonites from Sierra Espuña. All the specimens are figured at natural size except for A (× 0.7). A. Phymatoceras (Furloceras) chelussi (Parisch and Viale), MC.180.8, Middle Toarcian, Gradata Zone, Morrón Chico section 1.8 m. B. G. speciosum (Janensch), MC.1000.1, Upper Toarcian, Reynesi Zone, Morrón Chico section 10 m. C. Hecticoceras (Chanasia) bannense Elmi, MI.251.1, Lower Callovian, Gracilis Zone, Malvariche

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Taramelliceras (Ta.) cf. trachinotum (Oppel) (Fig. 6E), Ta. (Ta.) sp., Glochiceras (Lingulaticeras) gr. crenosum (Quenstedt), Pseudowaagenia aff. micropla (Oppel), Ataxioceras (Schneidia?) sp., and Ataxioceras sp., along with abundant Sowerbyceras silenum (Fontannes), which dated the uppermost Platynota or the Strombecki Zone. The remainder Lower Kimmeridgian (Strombecki or Divisum Zone) was recorded 2.6 m above, with the record of Nebrodites (Nebrodites) gr. hospes (Neumayr), Ne. (Ne.) sp., Ta. (Ta.) subcallicerum (Gemmellaro) (Fig. 6D), Ta. (Ta.) cf. pseudoflexuosum (Favre), Ta. (Ta.) sp., and Streblites sp. (Fig. 6). In the last 6 m appeared scarce and badly preserved Ta. (Ta.) gr. pugile (Neumayr), Discosphinctoides (Di.) aff. capillaceous (Dumortier) with Ho. mediterraneum (Neumayr) and So. silenum (Fontannes), which belong to the Divisum Zone. The Upper Kimmeridgian was recognized in the top of four nodular-breccioids levels at 260 m in the Malvariche section (Figs. 2 and 6). Ammonites were badly preserved as reworked inner moulds with common fragmentation, imbrication and generalized disarticulation of body chambers and phragmocones along the septa. The recorded assemblage is dominated (more than 80%) by Phylloceratina [mainly So. loryi (Munier-Chalmas) morphs loryi and pseudosilenum, and few Ho. polyholcum (Benecke)]. The four horizons studied were attributed to the Beckeri Zone, with a similar ammonite assemblage composed, as more relevant, of Hybonoticeras (Hy.) beckeri beckeri (Neumayr) (Fig. 6H), Hy. (Hy.) beckeri harpephorum (Neumayr) (Fig. 6G), Hy. (Hy.) gr. beckeri (Neumayr), Ta. (Ta.) pugile pugile (Neumayr), Ta. (Ta.) gr. pugile (Neumayr), Glochiceras (Lingulaticeras) sp., Shaireria cf. episa (Oppel), Aspidoceras cf. sesquinodosum (Fontannes), Torquatisphinctes cf. laxus Olóriz, Biplisphinctes cf. uracensis Berckhemer and Discosphinctoides (Discosphinctoides) sp. (Fig. 6) No Tithonian ammonites were recorded in the Malvariche or in the Prat Mayor section. Thus, the Upper Tithonian was evidenced by the FAD of hyaline calpionellids, and the record of the Crassicollaria Zone, at 295 m in the Malvariche and 285 m in the Prat Mayor sections (Fig. 2). Finally, the Tithonian/Berriasian boundary was approached by the bloom of large and isometric C. alpina (Calpionella Zone) at 330 m in the Malvariche and 305 m in Prat Mayor sections.

6. Paleoenvironmental interpretation The evolution of the Jurassic from the Malaguide at Sierra Espuña is comparable to other sectors of the Tethyan paleo-

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margins belonging to Internal and External Zones: the Subbetic (S Spain, Vera, 1988), the Venetian Alps (N Italy, Zempolich, 1993), the Apennines (Central Italy, Colacicchi et al., 1999), the Trapanese, (W Sicily, Catalano et al., 2002) or the Ghomarids (N Africa, Maate, 1996). During the Jurassic it evolves as a passive margin, beginning with the pre-rifting stage, followed by the platform break-up of the rifting stage (starting from the Domerian, Lavinianum Zone), and finally the drifting stage (from the Lower Callovian, Gracilis Zone). As shown in Fig. 7, over the earliest Liassic dolostones, the outcropping pre-Domerian deposits are built up by oo-oncolitic limestones, sometimes breccioids, evolving upwards to crinoidal limestones. These are interpreted as restricted inner-shelf deposits of oolitic shoals, nearby algal and/or crinoidal meadows. Accordingly, the recorded faunas are solely abundant and well-diversified shallow-water benthos such as algae, crinoids, sponges, gastropods, bivalves (pectinids, ostreids and Lithiotis), brachiopods, solitary corals, echinoderms, and benthic foraminifers, among others. These benthic faunal assemblages are dominated by suspension feeders, with little resedimentation processes, even lying in living position (Lithiotis, corals). In such a context, the recorded upwardly thickening and coarsening parasequences (more developed in the Malvariche section; Fig. 3) may be interpreted as upwardly shallowing cycles. Above, the Domerian-Toarcian guide interval of alternating yellowish marly/silty limestones (slightly nodular) with ferruginous oolites and oncoids, records the beginning of the rifting stage with the break-up of the platform (drowning unconformity). This event is linked to a tectonic pulse (active listric faulting and tilting blocks), evidenced by the variable thicknesses and lithofacies among sections (Fig. 3) and the presence of neptunian dykes (e.g. Morrón Chico section, Fig. 3). The restricted inner platform, where the underlying oolitic limestones developed, may drown at relatively shallow depth, leading to drastic reduction of carbonate productivity with changes in current circulations and water chemistry, probably with contribution of upwelling of eutrophic water, rich in Fe–Mn oxi-hydroxides (influx of trophic resources and plankton coming from the open sea into the platform). Thus, the faunal assemblages are alternatively dominated by benthos of low diversity (mainly brachiopods, echinoderms, bivalves), and, for the first time, pelagic assemblages; stunted ammonites and belemnites of low diversity, with intense reworking, sometimes wrapped by ferruginous centimetric-decimetric oncoids. The interpreted depositional environment may be an open shelf, with variable depth, water chemistry and hydrodynamics, due to the intricate bottom topography (block faulting

section 251 m. D. Rehmannia (Rehmannia) freii (Jeannet) sensu Cariou (1980), MI.251.3, Lower Callovian, Gracilis Zone, Malvariche section 251 m. E. M. gracilis (Spath), MI.251.2, Lower Callovian, Gracilis Zone, Malvariche section 251 m. Fig. 5. Ammonites du Jurassique inférieur et moyen de la Sierra Espuña. Tous les spécimens sont représentés à grandeur naturelle sauf A (× 0.7). A. Phymatoceras (Furloceras) chelussi (Parisch et Viale), MC.180.8, Toarcien moyen, Zone à Gradata, section de Morrón Chico 1,8 m. B. G. speciosum (Janensch), MC.1000.1, Toarcien supérieur, Zone à Reynesi, section de Morrón Chico 10 m. C. Hecticoceras (Chanasia) bannense Elmi, MI.251.1, Callovien inférieur, Zone à Gracilis, section de Malvariche 251 m. D. Rehmannia (Rehmannia) freii (Jeannet) sensu Cariou (1980), MI.251.3, Callovien inférieur, Zone à Gracilis, section de Malvariche 251 m. E. M. gracilis (Spath), MI.251.2, Callovien inférieur, Zone à Gracilis, section de Malvariche 251 m.

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Fig. 6. Upper Jurassic ammonites. All the specimens at natural size, except for B (× 0.20). A. Perisphinctes (Dichotomoceras) bifurcatoides Enay, PM.241.6-1, Middle Oxfordian, Bifurcatus Zone, Prat Mayor section 241.6 m. B. Passendorferia (Passendorferia) aff. uptonoides, PM.243.7-1, Upper Oxfordian, Planula Zone, Prat Mayor section 243.7 m. C. Nebrodites (Nebrodites) gr. hospes (Neumayr), PM.252-1, Lower Kimmeridgian, Strombecki-Divisum? Zone, Prat Mayor section 252 m. D. Taramelliceras (Taramelliceras) subcallicerum (Gemmellaro), PM.252-2, Lower Kimmeridgian, Strombecki-Divisum? Zone, Prat

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and tilting). Fig. 3 shows three tectonic blocks, limited by extensional faults. The intermediate block, which contains the Tres Carrascas, Prat Mayor and Morrón Chico sections, tends to sink eastward, developing less thickness (“ammonitico rosso” condensed limestones) in the Tres Carrascas section and a thicker succession with yellowish marly/silty limestones containing ferruginous oolites and oncoids in the Morrón Chico section. The generalized sediment starvation caused by the drowning of the platform led to a faunal accumulation as well as Fe–Mn oxi-hydroxides, which, together with the few available sediments, may have been distributed by waves/currents to the active depocenter (eastern parts of the tilted blocks; Fig. 3), tending toward smoothing relief. As in other Western Tethyan paleomargins, the tectonic subsidence during the progressing rifting stage in the Dogger (probably already from the uppermost Liassic) caused an incipient half-graben system in the area (Fig. 7). Sierra Espuña constitutes a relatively subsident depocenter, in an outer shelf to upper-talus paleogeographic context. Thus, the sedimentation during this period is dominated by pelagic or hemipelagic sediments (gravity flows and periplatform ooze), enriched in chert, coming from the contribution of siliceous planktonic organisms (radiolaria), especially in the upper part. Consequently, the recorded upwardly thickening and coarsening parasequences, with stacking of thicker parasequences above reflected the general progradation of the platform. Fauna is scarce in these well-stratified micritic/crinoidal limestones with chert. Benthos is represented almost exclusively by the disarticulated crinoid knuckles, which, together with oolites, came from the shallower part of the platform transported by gravity flows of sediment. Pelagic faunal assemblages are recorded only toward the upper part (Lower/Upper Bajocian and lowermost Callovian), in some condensed horizons at the top of strata. They are dominated by belemnites (often oriented, “belemnite battlefield” sensu Dolyle and Mac Donald, 1993) and/or complete ammonites with body-chamber, but no septa preservation (mostly pelagic free-swimmer forms such as Phylloceratids), which is interpreted as in situ burial, in a relatively deep environment (Fernández-López, 2000). On the contrary, the recorded Lower Callovian ammonites, which occur in relation to stratigraphic discontinuities, are truncated, corroded, fragmented inner moulds that, at times, can hardly be distinguished from

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mere intraclasts, together with epigenized shelly specimens; both are often domed by Fe–Mn laminae which are sometimes concentric around of the nucleus. Similar cephalopod concentrations appear in the Betic External Zones (Subbetic). These have been interpreted (Sandoval and Checa, 2002) as reworked assemblages formed on an irregular substrate subjected to energy pulses which would have led to the formation and repeated destruction of accumulation beds with different microfacies. As in many other sectors of the Tethyan paleomargin, the drifting stage starts around the Dogger/Malm boundary, changing the generalized tectonics by thermal subsidence. This stresses the differentiation of the horst and graben system, and then the diversification of depositional environments and facies (Figs. 2 and 7). During the Malm, the depositional environment for the Malaguide in Sierra Espuña is a mid-outer shelf that rises in some areas, becoming a distal pelagic swell with sedimentation of condensed ammonitico rosso, and related facies. In the study area, the condensed sedimentation linked to this raised sea-bottom started gradually from the Middle Oxfordian (Fig. 2). Among the two sections studied, a single tilted block or more likely, as in the Liassic, two different blocks can be interpreted, western side of which was relatively uplifted (situation of the Malvariche section; Fig. 2) while the eastern side was relatively sunk (Prat Mayor; Fig. 2). Because of this, over the interval with finely stratified marls and marly limestones, which are, consequently, thicker in the Prat Mayor section, the Middle–Upper Oxfordian to Kimmeridgian nodularbreccioid limestones were reduced and hiatal in the Malvariche section, while expanded and relatively with abundant resedimentation (pebbly mudstones) in the Prat Mayor section. Moreover, the relatively shallow depocenter at Malvariche presents only pelagic assemblages with ammonites in the uppermost Kimmeridgian, when the eustatic sea level was the highest of the Upper Jurassic, while the relatively deeper depocenter at Prat Mayor collected ammonites and other pelagic faunas from the Middle Oxfordian. In general, the Upper Jurassic ammonite assemblages are dominated by phylloceratids (especially by the eurythopic and ubiquist genre Sowerbyceras), recorded only in condensed nodular limestones, ammonitico rosso and related facies. As usual in this facies, cephalopods are variably preserved as

Mayor section 252 m. E. Taramelliceras (Taramelliceras) cf. trachinotum (Oppel), PM.249.4-12, Lower Kimmeridgian, Strombecki? Zone, Prat Mayor section 249.4 m. F. Orthosphinctes (Orthosphinctes) polygyratus (Reynecke) sensu Schairer morph colubrinus Oloriz, PM.246.4-15, Lower Kimmeridgian, Platynota? Zone, Prat Mayor section 246.4 m. G. Hybonoticeras (Hybonoticeras) beckeri harpephorum (Neumayr), MIII.1230-1250-15, Upper Kimmeridgian, Beckeri Zone, Malvariche III section 1230–1250 m. H. Hybonoticeras (Hybonoticeras) beckeri beckeri (Neumayr), MIII.1270-1280-53, Upper Kimmeridgian, Beckeri Zone, Malvariche III section 1270–1280 m. Fig. 6. Ammonites du Jurassique supérieur. Tous les spécimens sont représentés à grandeur naturelle sauf B (× 0.20). A. Perisphinctes (Dichotomoceras) bifurcatoides Enay, PM.241.6-1, Oxfordien moyen, Zone à Bifurcatus, section de Prat Mayor 241,6 m. B. Passendorferia (Passendorferia) aff. uptonoides, PM.243.7-1, Oxfordien supérieur, Zone à Planula, section de Prat Mayor 243,7 m. C. Nebrodites (Nebrodites) gr. hospes (Neumayr), PM.252-1, Kimméridgien inférieur, Zone à Strombecki-Divisum?, section de Prat Mayor 252 m. D. Taramelliceras (Taramelliceras) subcallicerum (Gemmellaro), PM.252-2, Kimméridgien inférieur, Zone à Strombecki-Divisum?, section de Prat Mayor 252 m. E. Taramelliceras (Taramelliceras) cf. trachinotum (Oppel), PM.249.4-12, Kimméridgien inférieur, Zone à Strombecki?, section de Prat Mayor 249,4 m. F. Orthosphinctes (Orthosphinctes) polygyratus (Reynecke) sensu Schairer morph. colubrinus Oloriz, PM.246.4-15, Kimméridgien inférieur, Zone à Platynota?, section de Prat Mayor 246,4 m. G. Hybonoticeras (Hybonoticeras) beckeri harpephorum (Neumayr), MIII.1230-1250-15, Kimméridgien supérieur, Zone à Beckeri, section de Malvariche III 1230–1250 m. H. Hybonoticeras (Hybonoticeras) beckeri beckeri (Neumayr), MIII.1270-1280-53, Kimméridgien supérieur, Zone à Beckeri, section de Malvariche III 1270–1280 m.

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Fig. 7. Synthetic Jurassic successions at Sierra Espuña, with indication of biofacies, microfacies and paleoenvironmental interpretation for the main lithofacies. M (mudstones), W (wackestones), P (packstones), G (grainstones). Legend for bioclasts in Fig. 2. Fig. 7. Succession synthétique du Jurassique de la Sierra Espuña, avec indication des biofaciès, microfaciès et interprétation paléoenvironnementale du lithofaciès principal. M (mudstones), W (wackestones), P (packstones), G (grainstones). Légende des bioclastes Fig. 2.

inner moulds, mostly reworked; frequent loss of bodychambers and truncations incompatible with the stratification. In the nodular-brecciate facies, inner moulds of ammonites are often fragmented and imbricate. Finally, at the end of the Jurassic the generalized thermal subsidence tends to deepen the paleomargin, while the huge relief caused by the horst and graben system is smoothed. Consequently, the area evolved to a basin in Lower Berriasian (probably already from the uppermost Tithonian) with deposition of periplatform limestones together with the local sedimentation by planktonic microfossils (calpionellids, foraminifers, radiolarians, as well as algae). 7. Conclusions A multidisciplinary study has enabled greater precision in updating the biostratigraphic framework and the paleoenvironmental interpretation of the Jurassic succession at Sierra Espuña. This area, which is one of the bigger, better exposed and more fossiliferous Jurassic outcrops of the Malaguide domain, can be considered a clue area to analyze the evolution of the Internal Zones of the Betic Cordillera.

As a whole, ammonite biostratigraphic data from the Internal Zones are scanty, and related only to the “Dorsal” and Malaguide domain such as the Sierra Espuña area. Particularly for this area, the previous biostratigraphic data, which comes from the 1960s and 1970s, need to be updated and revised. Thus, three previously studied and two new Jurassic sections at Sierra Espuña were sampled, leading to a more precise biostratigraphic ammonite framework. Ammonite assemblages have enabled the recognition of the Domerian, Lavinianum (Cornacaldense Subzone), Algovianum (Ragazzoni, Bertrandi, Accuratum and Levidorsatum Subzones) and Emaciatum (Solare and Elisa Subzones) Zones, the Lower Toarcian, Polymorphum and Serpentinum Zones, the Middle Toarcian, Bifrons and Gradata Zones, the Upper Toarcian, Reynesi Zone, the uppermost Lower/Upper Bajocian, the Lower Callovian (Bullatus and Gracilis Zones), the Middle and Upper Oxfordian (Transversarium, Bifurcatus, Bimammatum and Planula Zones) and the Lower and Upper Kimmeridgian (Platynota, Strombecki, Divisum and Beckeri Zones). Some of these zones and subzones are recognized, or documented with reported faunas, for the first time. As a whole, benthic assemblages dominated during the Lower Jurassic, while benthonic/planktonic assemblages

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developed within the Middle–Upper Jurassic. Ammonite taphonomy reveals the abundance of reworked assemblages with common truncation, imbrication and coating (by Fe–Mn oxides) of inner moulds or shells. Nevertheless, only occasionally during the Domerian–Lower Toarcian interval of alternating yellowish marly/silty limestones the faunal condensation mixed biostratigraphically recognizable horizons. The assemblages of ammonite faunas analyzed from the Domerian to the Kimmeridgian show a Mediterranean character. Thus, the bio-chronostratigraphic zonal/subzonal scheme was applied, with minimal changes, for Mediterranean Province (Cariou and Hantzpergue, 1997). The interpreted paleoenvironmental evolution of the Jurassic Malaguide at Sierra Espuña appears to be similar, and comparable in timing, to other perimediterranean Tethyan paleomargins. It evolves as a passive margin, with development of shallow carbonate platform, until the Domerian (Lavinianum Zone), when the platform break-up took place, starting the rifting stage. During this stage in the Dogger, the horst–graven system begins and the area was drowned at considerable depth. Then, from the Lower Callovian to the Middle Oxfordian, the drifting stage started, emphasizing the horst– graven system with development of condensed nodular limestones in the raised sea-floor.

Acknowledgements This research was economically co-financed by the research Projects BTE2001-3020, BTE2001-3029, BTE20000299 and BTE2003-01113 (Spanish Ministry of Science and Technology) and Research Groups GR00-222, GV04B-629 (Generalitat Valenciana) and RNM-178 (Junta de Andalucía). We are grateful to Professor A. Jiménez (University of Granada) for Photograph assistance. We are also indebted to Mr. D. Nesbitt for the revision of the English text.

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