Jurassic biostratigraphy and paleoenvironmental evolution of the ...

Jurassic biostratigraphy and paleoenvironmental evolutionof the Malaguide complex from SierraEspuña (Internal Betic Zone, SE Spain)

Biostratigraphie du Jurassique et évolution paléoenvironnementaledu 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, Spainb 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 metamorphicrocks. Only the “Dorsal” and the Malaguide domains include fossiliferous Jurassic successions, as in Sierra Espuña (SE Spain), which is oneof the bigger and well-exposed Jurassic outcrops of the Internal Zones. Collected Ammonite assemblages update and improve the precision ofprevious biostratigraphic data by the recognition of: the Domerian (= Upper Pliensbachian, in the Mediterranean Domain) Lavinianum (Cor-nacaldense Subzone), Algovianum (Ragazzoni, Bertrandi, Accuratum and Levidorsatum Subzones) and Emaciatum (Solare and Elisa Sub-zones) Zones; the Lower Toarcian Polymorphum and Serpentinum Zones; the Middle Toarcian, Bifrons and Gradata Zone; the Upper Toar-cian 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 paleo-margins. The biostratigraphic precision along with the litho- and biofacies analyses has enabled the interpretation that the Malaguide paleo-margin evolved as a passive margin, developing shallow carbonate platforms, until the Domerian (Lavinianum Zone). Then, the platformbroke up (Domerian, Lavinianum Zone–Upper Toarcian, Reynesi Zone) with the beginning of the rifting stage, beginning the development ofhorst–graben systems and the coeval drowning of the area. This stage ended in the upper Lower Callovian (Gracilis Zone) to the MiddleOxfordian (Transversarium Zone) interval, starting the drifting stage, which accentuated the horst–graben systems, leading to the depositionof 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 sontessentiellement composées de roches métamorphiques plus anciennes. Seuls, la Dorsale bétique et le Domaine Malaguide, où les roches sonten général épargnées par le métamorphisme, comprennent des successions fossilifères jurassiques d’intérêt biostratigraphique. C’est le cas dela Sierra Espuña où on peut observer un des affleurements les plus complets et mieux exposés des Zones Internes. Les associations d’ammonitespermettent 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).

Geobios 39 (2006) 25–42

http://france.elsevier.com/direct/GEOBIO/

0016-6995/$ - see front matter © 2005 Elsevier SAS. All rights reserved.doi:10.1016/j.geobios.2004.09.002

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 moyenet 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 Zonesà 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 paléomargesde la Téthys méditerranéenne. La précision biostratigraphique et l’analyse des lithofaciès et des biofaciès nous ont permis d’interpréter lapaléomarge 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, Zoneà Reynesi) liée au commencement de la phase de « rifting », caractérisée par le développement d’un système de horsts et grabens et l’enfoncementde cette région. L’extension se poursuit entre le Callovien inférieur (Zone à Gracilis) et l’Oxfordien Moyen (Zone à Transversarium), enindiquant le début d’une phase de « drifting » qui aurait déclenché la réactivation du système de horsts et grabens, conduisant au dépôt decalcaires 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 placeunder distensive tectonic conditions related to Tethyan rift-ing. Although, the rifting age has been considered quite simi-lar throughout the cordillera, controversy continues concern-ing the synchronism versus diachronism for the pre-, syn-and postrifting periods in the different domains into whichthe Betic Cordillera has traditionally been divided: the Inter-nal and the External Zones.

The External Zones belong to the South Iberian Paleomar-gin and consist of post-Triassic unmetamorphosed rocks.Thus, the Jurassic paleogeographic evolution and the age ofthe onset of the rifting (Carixian = Lower Pliensbachian), andthe post-rifting phase (boundary Middle/Upper Jurassic) hasbeen well-characterized (Vera, 1988). On the contrary, theInternal Betic Zones belong to a microplate (Mesomediterra-nean Terrain, Guerrera et al., 1993) derived from the NorthAfrican continental margin, which collided against the Exter-nal Zones during the Early Miocene. These zones are built upby the stacking of four complexes (in order upwards): Nevado-filabride, Alpujarride, Malaguide and “Dorsal”. The Nevado-filabride and Alpujarride are composed mainly of Paleozoicand Triassic (and older), metamorphic rocks, while theMalaguide and “Dorsal” Complexes include unmetamor-phosed Paleozoic (Malaguide) and Meso-Cenozoic (Malagu-ide and “Dorsal”) sedimentary rocks. In general, the scarcityof Jurassic unmetamorphosed successions, together with theintense tectonic activity, have hampered the dating of the mainJurassic events in the Internal Zones.

The Malaguide is the uppermost Complex (and, conse-quently, the most internal) of the Internal Zones, which out-crops mainly from Malaga Province (westward) to MurciaProvince (eastward). In contrast to the other complexes, theMalaguide Complex includes Jurassic sedimentary covers,favoring the analysis of the Jurassic evolution of the InternalBetic Zones. The Sierra Espuña area, in Murcia Province, is

probably the most extensive, and the best exposed Jurassicoutcrop belonging to the Malaguide in the Betic Cordillera.

Except for the pioneer work by Fallot (1945), the mainpapers on the Jurassic of Sierra Espuña are from the 1960sand 1970s (Peyre and Peyre, 1960; Mac Gillavry et al., 1963;Navarro and Trigueros, 1963; Paquet, 1962, 1969; Geyer andHinkelbein, 1971, 1974; Kampchuur et al., 1974; Seyfried,1978, among others). Almost no recent studies have beenmade on the biostratigraphy and the paleogeographic evolu-tion of the Jurassic of Sierra Espuña. In the present work, weanalyze some classical Jurassic sections, together with newsections, in order to update the biostratigraphic frameworkand to approach the paleoenvironmental evolution of theJurassic Malaguide from Sierra Espuña. Moreover, this willimprove the knowledge of the Jurassic of the Internal BeticZones, in addition to providing a fuller understanding of theExternal 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 Malagu-ide outcropping area of Sierra Espuña bounds tectonicallywith the Alpujarride Complex to the SE, and with the Exter-nal Betic Zones (Subbetic) to the NW. Laterally, the nearestoutcrop of Jurassic Malaguide in the region is located 40 kmwestward, near Vélez Rubio in the Province of Almeria(Castillón Fm., Geel, 1973).

The outcropping Malaguide Complex in Sierra Espuña iscomposed of two tectonic units (Martín-Martín, 1996); Mor-rón de Totana and Perona (Fig. 1). The Morrón de TotanaUnit is the footwall while the Perona Unit is the hanging wall,which, paleogeographically came from a more proximal posi-tion (Martín-Martín and Martín-Algarra, 1997). Both unitsinclude a marine Jurassic sedimentary cover, although in the

26 J.E. Caracuel et al. / Geobios 39 (2006) 25–42

Perona Unit only outcrops Liassic sediments and have areduced areal extension. In this unit, only one section wasselected for studying (Perona section; Fig. 1). In the Morrónde Totana Unit, the Jurassic is well developed, outcroppingwith lateral continuity along more than 12 km (Fig. 1). Here,four sections were analyzed, these being spaced 2–5 km fromeach 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 Espuñacome from Fallot (1929, 1945), who studied the Jurassic suc-cessions at Morrón Chico and Prat Mayor. This author rec-ognized, within the carbonate succession of the platform, aferruginous oolith-rich interval (0.5–3 m thick) with late Lias-sic ammonites (Dumortieria sp. and Pleydellia sp.). This

Fig. 1. Geographical (upper) and Geological (lower) sketches with the location of the 5 studied sections at Sierra Espuña. Legend: 1. Undifferentiated Quater-nary. 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 sandsto-nes.Fig. 1. Croquis géographique (supérieur) et géologique (inférieur) avec l’emplacement des 5 sections étudiées dans la Sierra Espuña. Légende : 1. Quaternaireindifférencié. 2. Plate-forme carbonatée éocène. 3. Marnes et calcaires marneux du Crétacé inférieur. 4. Marnes, calcaires et calcaires noduleux du Jurassiquesupérieur. 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.

27J.E. Caracuel et al. / Geobios 39 (2006) 25–42

guide-level was first noted by Villasante (1912), who assignedit a Lusitanian to Kimmeridgian age.

Later on, Peyre and Peyre (1960) and Navarro andTrigueros (1963) fixed the age of the ferruginous oolith-richinterval studied by Fallot (1945), based on the faunas (ammo-nites and brachiopods) collected in the Prat Mayor section.Peyre and Peyre (1960) recognized abundant ammonites ofthe genera Lytoceras, Coeloceras, Reynesoceras, Ariet-iceras, Harpoceras and Protogrammoceras, and brachio-pods (Spiriferina, Terebratula and Rhynchonella), and usedthem to date the Middle Domerian (Domerian = Upper Pliens-bachian, in the Mediterranean Domain). No more macro-fauna was collected in the remaining Jurassic succession,although the record of microfacies enriched in crinoids, fora-minifers (Involutina, Nodosaria and Lenticulina), Stomi-osphaera and Cadosina toward the upper part, make feasibleto assume the existence of the Middle and Upper Jurassic, asin 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 Juras-sic from Sierra Espuña, including the analysis of sections inthe Morrón de Totana and Perona tectonic units. Accordingto Peyre and Peyre (1960) and Paquet (1969) proposed aMiddle Domerian (Upper Pliensbachian) age for the ferrugi-nous oolith-rich level of the Liassic in the Prat Mayor sec-tion, based on the record of Fuciniceras cf. curionii (Me-neghini), Protogrammoceras bassanii (Fucini), Arieticerasbertrandi (Kilian) and Ar. fuccinii (Del Campana), amongothers. In the Perona section, the same level was dated byPaquet, using brachiopods as Lower Pliensbachian, leadingto the suggestion that the ferruginous oolith-rich interval mightbe diachronous.

According to Paquet (1969), the Lower/Middle Jurassicboundary in the Morrón de Totana Unit (probably studied inthe Prat Mayor section), begins with a thick oolitic-limestonelevel (25 m) with gastropods and bivalve fragments, evolvingto whitish-gray micritic limestones with filaments (10 m), andlater on, well-bedded gray, slightly marly, pelagic limestones(25 m) with “Cancellophycus”, filaments, and Globochaetealpina Lombard belonging to the Middle Jurassic. In theUpper Jurassic analyzed in the same localities, including theFuente Blanca section (here called Prat Mayor), Paquet (1969)recognized well-bedded gray limestones with filaments at thebase, slightly marly limestones with Globochaete above andgrayish-white, more or less nodular, limestones with Calpi-onella alpina Lorenz, Stomiosphera minutissima (Colom),G. alpina Lombard, Textulariidae and Lageniidae towardsthe upper part.

Geyer and Hinkelbein (1971, 1974) focused on the detailedbiostratigraphy of the Liassic ferruginous oolith-rich inter-val, outcropping in the Morrón de Totana (Morrón de Alhamasection, for these authors) and Prat Mayor (Fuente Blancasection, for these authors). Geyer and Hinkelbein (1971, 1974)made a detailed correlation of this 5 m thick section, dating itas the Upper Pliensbachian (on the basis of a few and badlypreserved forms of Arieticeras/Canavaria/Fontanelliceras,

Lioceratoides and Catacoeloceras) in the lower part of PratMayor section. In the upper part of Morrón de Totana sec-tion, 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), Dumor-tieria sp. and Pleydellia sp., as more relevant]. Thus, theseauthors assumed an Upper Pliensbachian–Aalenian? age forthe complete interval in both sections, avoiding the interpre-tation of the diachroneity proposed by Paquet (1962, 1969).

Kampchuur et al. (1974) assigned 90 m of white ooliticlimestones with algae (Thaumatoporella), ostracods, and fora-minifers to the pre-Domerian Liassic. Over these shallow plat-form carbonates appear a few meters of ferruginous oolith-rich limestones. These authors accepted the dating by Paquet(1969) for this guide horizon as Middle Domerian in the Mor-rón de Totana Unit, and then the subsequent diachrony ofsuch level. The Dogger encompasses 100–140 m thick ofoolitic limestones with crinoids, miliolids and ostracods,evolving to biopelmicrites, rich in echinoderms, “filaments”,Ammodiscus, and lagenids. The Upper Jurassic is composedof 90 m of massive limestones, occasionally nodular, withradiolaria, Globuligerina, G. alpina Lombard, and ostra-cods, with Saccocoma and calpionellids in its upper part.

Seyfried (1978) studied some Jurassic sections at Casas yPozos de Murcia (equivalent, in part to the Prat Mayor andTres Carrascas sections here) recognizing the ferruginousoolith-rich level with abundant Middle Domerian faunas. TheMiddle Jurassic materials are represented by 65–70 m ofoolitic/crinoidal limestones, and gray laminated limestonescontaining trace fossils, interbedded with turbiditic levels withresedimented oolites and scarce Upper Bajocian ammonites(Spiroceras sp., Nannolytoceras sp.). The overlying UpperJurassic (approximately 45 m thick) includes calcareous brec-cias, pelites and fluxoturbidites with foraminifers, bivalves(Inoceramus) and Oxfordian ammonites (Phylloceras sp.,Holcophylloceras sp., Sowerbyceras sp., Arisphinctes sp. andDichotomosphinctes? sp.) at its base, with massive lime-stones above and well bedded limestones (pelmicrosparite andbiopelmicrite) with foraminifers, crinoids, and echinoids inits upper part.

Recently, Caracuel et al. (2001) and Martín-Rojas et al.(2002) described the general stratigraphy of a new Jurassicsection near Malvariche, where the lithofacies are similar tothose of the classical outcrops at Prat Mayor and MorrónChico. In the Malvariche section, these authors found ammo-nite assemblages indicating the Middle Domerian (Al-govianum Zone; ferruginous oolith-rich limestones), theLower Callovian [Bullatus and Gracilis (= Patina zone, sensuSequeiros, 1974)], and the uppermost Kimmeridgian (Beck-eri Zone).

4. The sections studied: stratigraphic data

Five Jurassic sections were studied in Sierra Espuña; thethree classical sections already mentioned from Fallot (1945)


to Seyfried (1978); Prat Mayor, Morrón Chico and Perona,(Fig. 1), and two new ones (Malvariche and Tres Carrascassections; Fig. 1). Sections were selected to cover the Morrónde Totana tectonic Unit (Malvariche, Tres Carrascas, PratMayor and Morrón Chico sections; Figs. 1–3) and the PeronaUnit (Perona section; Figs. 1 and 3), evenly spaced along theSierra Espuña.

The present study was focused in the Prat Mayor and Mal-variche sections (Fig. 2) since they are easily accessible, arelittle tectonized and contain the most complete, and fossil-rich successions. In sections at Tres Carrascas, Morrón Chicoand Perona, only the Liassic (especially the ferruginous oolith-rich limestone interval) was studied.

Along with the stratigraphical and sedimentological analy-sis, more than 140 thin sections were used for characterizingthe microfacies, textures and microfossil content; particu-larly the Globuligerina and calpionellids, during the UpperJurassic, which have potential biostratigraphic interest. Mac-roinvertebrates (more than 500 specimens), mainly ammo-nites and brachiopods, were sampled in favorable facies forbiostratigraphy.

4.1. Lower Jurassic

The Lower Jurassic was analyzed in all sections studied. Itis composed of oo-oncolitic limestones, sometimes brecci-ated, evolving to crinoidal limestones, with an interval of fer-ruginous silty limestones at the top. In the Malvariche andPrat Mayor sections, the lower boundary is better exposedand makes contact tectonically with massive saccaroid dolo-stones, sometimes attributed to the earliest Jurassic. The thick-ness of the outcropping Lower Jurassic, which sometimes canbe 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 thepresence of Lithiotis-rich levels, typical for the Liassic Peri-mediterranean Tethys. Moreover, Kampchuur et al. (1974)suggests a Sinemurian to Pliensbachian age for its micro-fauna. By contrast, the upper part with ferruginous silty lime-stones were easily dated in all sections, ranging from theDomerian (= Upper Pliensbachian; Lavinianum Zone, Cor-nacaldense Subzone) to the Upper Toarcian (Reynesi Zone),according to the ammonite assemblages collected.

In all sections studied, the lower part of the succession iscomposed of oo-oncolitic, evolving to crinoidal limestones,showing decametric thickening and upwardly coarseningparasequences (10–25 m thick), quite stable both in thick-ness and lithofacies variation, with no evident stacking trend.The elementary parasequence appears to be built up by whiteoo-pisolitic limestones evolving to pinkish oncolitic–rodo-litic limestones, sometimes breccioids, and topped by an algalcrust and/or an intensely bioturbated/bored surface. Cross-bedded grainstones are usual in the lower part of the parase-quences.

Microfacies are mainly grainstones to packstones (occa-sionally rudstones) with oolites, pisolites and/or oncolites and,

secondarily, algae [Cayeuxia piae Frollo, Palaeodasycladusmediterraneus (Pia)], ostracods, sponges, and benthic fora-minifers. Some levels are rich in Textulariidae, Siphoval-vulina sp., and transitional forms of Mayncina termieri Hot-tinger and Lituosepta compressa Hottinger, which arecharacteristics of the protected Liassic platform of the Medi-terranean (Sartorio and Venturini, 1988). Benthic macro-fauna such as gastropods, bivalves (pectinids, ostreids andLithiotis), brachiopods, solitary corals, echinoderms are oftenabundant (Fig. 2). Generally, they are found in living posi-tions, as for example the characteristic Lithiotis horizon ofthe upper part of the elementary parasequences.

The upper part of the Lower Jurassic succession is built upby 2–12 m of alternating yellowish marly/silty limestones,occasionally slightly nodular, with levels of ferruginousoolites and/or decimetric Fe–Mn oncoids, which are formedby concentric laminae around a nucleus (meter levels 110–122 in Malvariche and 60–65 in Prat Mayor; Fig. 2). Only insection at Morrón Chico, does the base of this interval show akarst-like irregular surface sinking more than 2 m on theunderlying crinoidal limestones. This characteristic interval,which can be used as a guide-horizon for geological map-ping, is well-developed and widespread in Sierra Espuña.Some sections contain a similar interval made up of yellow-ish marly/silty limestones, although thinner, less continuousand fossiliferous (meter levels 88–92 in Malvariche and20–25 in Prat Mayor; Fig. 2).

In the five sections studied, the interval of ferruginous siltylimestones with Fe-oolites is rich in well-preserved macro-fauna with neomorphosed ammonite and brachiopod shells,together with oriented belemnites, bivalves, gastropods, andechinoderms (Fig. 3). Trace fossils (Thalassinoides, Plano-lites and Chondrites) are widespread in the marly levels. Asshown in Fig. 3, the ammonites collected have enabled thecharacterization of discrete and discontinuous horizons withinthe Domerian (Lavinianum, Algovianum and EmaciatumZones) and the Toarcian (Polymorphum, Serpentinum,Bifrons, Gradata and Reynesi Zones).

4.2. Middle Jurassic

The studied Middle Jurassic sections at Malvariche andPrat Mayor are 138 and 145 m thick, respectively (Fig. 2).They are composed mainly of well-stratified micritic/crinoidallimestones with abundant chert in nodules and ribbons,increasing toward the upper part. At the base, the micritic/crinoidal limestones alternate with thick oolitic limestoneslevels, which resemble that of the Lower Jurassic. Towardthe upper part, some levels composed by micritic limestoneshow incipient nodularization, with abundant trace fossils(mainly Thalassinoides), developing two multiple hardgrounds at the top, with an accumulation of glauconite orferruginous crusts and faunal concentrations, includingammonites and occasionally oriented belemnites (“belem-nite battlefields” sensu Doyle and MacDonald, 1993).

As a whole, the lower and middle part of the Middle Juras-sic is composed of upwardly thickening and coarsening


parasequences (2–5 m thick), with stacking of upwardlythicker parasequences. Microfacies range from wackestonesto packstones (occasionally crinoidal grainstones) withcrinoids, along with thin-shelled bivalves (“filaments”), radi-olaria, benthic and planktonic foraminifers, and other mac-roinvertebrate fragments. Apart from disarticulated crinoidossicles, benthic macrofauna are almost absent in the MiddleJurassic, in contrast to the Lower Jurassic. Planktonic mac-rofauna is also scarce, but in the top of some levels, espe-cially toward the upper part, cephalopods proved widespread(ammonites and belemnites).

In these levels, better developed in the Malvariche sec-tion, ammonites assemblages were collected, enabling recog-nition of the Lower Bajocian, based on the record of a speci-men of Skirroceras sp. Also recognized were the LowerCallovian [Bullatus Zone; based on the record of Homoeo-planulites sp., Macrocephalites sp., and Kheraiceras cf. bul-latus (d’Orbigny)], and the Gracilis Zone (Patina Zone sensuSequeiros, 1974) with abundant and significant ammonites,especially Macrocephalinae and Reineckeidae. No otherammonite faunas were found in the Middle Jurassic.

4.3. Upper Jurassic

The Upper Jurassic features at Malvariche and Prat Mayordiffer somewhat with regard to lithofacies and faunal assem-blages, although the thicknesses are quite similar, 80 and 90 m,respectively (Fig. 2). As a whole, the succession is composedby finely stratified marl and marly limestones which evolvedto stratified limestones stacked in thickening upward parase-quences (1–2 m thick). Then, massive nodular limestones(sometimes brecciated) alternate with stratified limestones andmarls, arranged in upwardly thinning parasequences. Tex-tures and microfacies are highly variable, ranging from pel-loidal mudstones to intraclastic packstones (occasionallycrinoidal grainstones) with Globuligerina (at the base), fila-ments, Saccocoma, radiolaria, Globochaete, Stomiosphaera,Cadosina, macroinvertebrate fragments (mainly ammonitesand belemnites) and calpionellids (in the upper part).

In both sections (Fig. 2), above the multiple Fe–Mn crustsdated as Lower Callovian (Gracilis Zone) outcrops a 5–10 mthick interval of marly limestones and marls, finely stratified,and texturally mudstones to wackestones rich in Globulige-rina, attributed to the Callovian?–Oxfordian. In the Malvar-iche section, 7 m of slightly nodular marly limestones appearin upwardly thickening parasequences. Towards the top, thereis an irregular massive breccioid bank, 4 m of slightly nodu-lar marly limestones organized in upwardly thinning parase-quences, and a characteristic crinoidal bank with an erosivebase. Just below this crinoidal bank, ammonite assemblageswere collected from the uppermost Kimmeridgian (BeckeriZone). These slightly nodular marly limestones stacked in

upwardly thinning parasequences continues 15 m more overthe encrinitic bank, and then change to upwardly thickeningparasequences; the facies change gradually to alternatingmarly/calcareous nodular limestones, often brecciated. Theupper 20 m are composed of crinoidal levels and marly inter-vals with microfacies enriched in hyaline calpionellids whichcharacterized the Upper Tithonian.

In the Prat Mayor section above the marly limestones withGlobuligerina, outcrop 50 m of ammonitico rosso nodularlimestones alternating with thick breccioids banks, orga-nized in upwardly coarsening and thickening parasequences(2–4 m thick). In this interval, ammonite assemblages char-acterizing the Middle–Upper Oxfordian and the Lower–Middle? Kimmeridgian were collected. In contrast to the Mal-variche section, no ammonites from the Upper Kimmeridgianwere found. The upper part of section at Prat Mayor appearssimilar to Malvariche, although more reduced and with char-acteristic breccioid banks. In both sections, the calpionellidsZones of Chitinoidella, Crassicollaria and Calpionella wererecorded.

5. Ammonite biostratigraphy

Jurassic ammonite faunas belonging to the Internal Zoneof the Betic Cordillera has been rarely and discontinuouslyreported, and in all cases from the non-metamorphosedMalaguide and “Dorsal” domains (Fallot, 1929, 1931–1934,1945; Peyre and Peyre, 1960; Azema, 1960, 1961; Paquet,1969; Geyer and Hinkelbein, 1971, 1974; Seyfried, 1978 andCaracuel et al., 2001). Biostratigraphic data from SierraEspuña come mainly from Geyer and Hinkelbein (1974); Sey-fried (1978) and Caracuel et al. (2001), who described ammo-nite assemblages belonging to the Domerian, Middle–UpperToarcian, Upper Bajocian, Oxfordian and Upper Kimmerid-gian. For the present paper, more than 500 macroinverte-brates, mainly ammonites, were collected in order to com-plete and to revise the biostratigraphic framework from theDomerian to the Kimmeridgian in the three previously stud-ied and two new Jurassic sections at Sierra Espuña. Theammonite zonal/subzonal scheme in Cariou and Hantzper-gue (1997) for the Mediterranean Domain was used in theDomerian, Toarcian and Callovian stages.

Domerian ammonites show good preservation with neo-morphosed shells, sometimes ferruginous, and mostly withpreserved living chambers; phragmocone septa are consis-tently preserved (Figs. 4 and 5). There appears to be no tapho-nomic size bias, although the smaller ammonoids (occasion-ally fragments) are sometimes found in the interior of Fe–Mnoncoids, with a variable mode of preservation.

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


Fig. 3. Detailed successions in the five Domerian–Toarcian sections studied; interval of alternating yellowish marly/silty limestones, occasionally slightlynodular, with levels of ferruginous oolites and/or decimetric oncoids. Recognized Zones and Subzones (according to Cariou and Hantzpergue, 1997) are shadedin 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 légère-ment 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.


In the lower level of yellowish silty/limestones orsilty/marly limestones of the Malvariche section (meter lev-els 88–92), which contains abundant bivalves, ammonite arescarce and fragmentary; we have recognized Lytoceras vil-lae Meneghini, Fuciniceras gr. isseli (Fucini), Fu. corna-caldense (Taush) and Fieldingiceras fieldingii (Reynes), indi-cating that, at least in this section, the Lower Domerian(Lavinianum Zone, Cornacaldense Subzone) is representedin Sierra Espuña.

In Malvariche (meters 110–122) and Prat Mayor (meters60–65) the alternating yellowish marly/silty limestones, occa-sionally slightly nodular, with levels of ferruginous oolitesand oncoids (Figs. 2 and 4), have supplied abundant, diversi-fied and relatively well preserved ammonites: Ly. villaeMeneghini (Fig. 4A), Fi. fieldingii (Reynes) (Fig. 4B), Fu.cornacaldense (Taush) (Fig. 4C), Protogrammoceras aequi-ondulatum (Bettoni), Pr. aff. ilurcense Braga, Arieticerasalgovianum (Oppel) (Fig. 4E), Ar. disputabile (Fucini)(Fig. 4F), Ar. amalthei (Oppel), Ar. bertrandi (Kilian), Lep-taleoceras accuratm (Fucini), Le. ugdulenai (Gemmellaro),Becheiceras bechei (Sowerby), Reynesoceras acanthoides(Reynes), Re. ragazzonii (Hauer) (Fig. 4D), and Parstch-iceras aff. proclive (Rosemberg). According to Braga (1983),this ammonite assemblage dates the Middle Domerian(Algovianum Zone; Ragazzoni, Bertrandi and AccuratumSubzones) and possibly the Lower Domerian [LavinianumZone, 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 ispossible that, with a detailed sampling, the three MiddleDomerian Subzones could be separated, given that differentsamples (some with several ammonites species) can have dif-ferent lithologies.

In Tres Carrascas section, at 40 cm of the base (Fig. 3), wehave 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 sec-tion, 60 cm upward (samples TC.100C) we have found Pleu-roceras solare (Phillips), Em. sp., Lioceratoides fucinianus(Haas), Li. exapatus (Gemmellaro), and Neolioceratoideshoffmanni (Gemmellaro), which characterize the lower UpperDomerian (Emaciatum Zone, Solare Subzone). The sam-plings TC.100A and TC.100B, both in Tres Carrascas sec-tion (Fig. 3) contain Em. archimedis Fuccini, Em. lottii (Gem-mellaro) (Fig. 4G), Em. timaei (Gemmellaro) (Fig. 4I), Em.sp., Li. serotinus (Bettoni), Li. micetoi (Fucini) and Ne. hoff-manni (Gemmellaro). This assemblage dates the uppermostDomerian (Emaciatum Zone, Elisa Subzone).

Domerian/Toarcian transition has been recognized in thelower part of the Morrón Chico section (Fig. 3), with the fol-lowing ammonite assemblage: Li. lorioli (Bettoni), Li. sp.,Ne. hoffmanni (Gemmellaro) Ne. schopeni (Gemmellaro),Canavaria sp., Ca. gregalis Fucini and Fontanelliceras fon-tanellense (Gemmellaro). Braga (1983) proposed that thisassemblage may correspond to the uppermost Domerian (ElisaSubzone)–lowermost Toarcian (Polymorphum Zone).

As in the External Zones (Subbetic) of the Betic Cordil-lera (see Braga, 1983), the Hildoceratidae (Harpoceratinaeand Hildoceratinae) and Lytoceratidae clearly dominate theDomerian ammonite assemblages, indicating its typical Medi-terranean character. Dactylioceratinae are also abundant inthe Ragazzoni Subzone, whereas other groups such as Phyl-loceratidae, Amaltheidae and Liparoceratidae, though alsopresent, are scarce.

Toarcian materials are clearly represented in the PeronaUnit (Fig. 3) where some specimens of Dactylioceras (Eodac-tylites) sp. and Hildaites striatus Guex have been recorded,pointing to an Early Toarcian age (Polymorphum and Sepenti-num Zones).

Middle and Upper Toarcian sediments are well repre-sented in the Morrón Chico section, where a minimum offour fossiliferous levels can be differentiated (Fig. 3). Thelower one (40 cm upward of the base), reported above, rep-resents the Domerian/Toarcian transition. The following fos-siliferous level, located approximately 140 cm upward(samples MC.180), shows reduced net sedimentation withvery thinly laminated Fe–Mn layers which encrust either thediscontinuity surfaces or very well-preserved fossils, espe-cially ammonites. The following ammonite species occur:Hildoceras bifrons (Brugière) (Fig. 4J), Hi. semipolitumBuckman, Pseudomercaticeras venzoi Pinna, Osperleio-ceras bicarinatum (Zieten), Phymatoceras (Furloceras) che-lussi (Parisch and Viale) (Fig. 5A), Ph. (Fu.) venustulum(Merla), Mouterdeiceras sp., Catacoeloceras crassum (Youngand Bird), Ca. sp., Platystrophites latusi Levi-Seti and Oxypa-roniceras? sp. This ammonite assemblage represents theMiddle Toarcian, Bifrons Zone (Bifrons Subzone) and pos-sibly the base of the Gradata Zone. A single specimen ofMouterdeiceras sp. from 6.5 m from the base in the MorrónChico section indicates the Gradata Zone.According to Geyerand Hinkelbein (1974), who reported Upper Toarcian ammo-nites from this section, some specimens of Geczyceras spe-ciosum (Janensch) (Fig. 5B), Pseudogrammoceras sp. andLytoceras 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 exsitu Dumortieria sp. indicates the upper part of the ReynesiZone.

Middle Jurassic ammonite assemblages were better regis-tered in the Malvariche section. Just below the lower level ofa multiple limonite crust (230 m in Fig. 2) we sampled scarceand badly preserved fauna (Skirroceras sp.), which can beattributed to the upper Lower Bajocian. The upper levels ofthese crusts have provided articulated crinoids, orientedbelemnites, and some deformed specimens of Homoeoplanu-lites sp., Macrocephalites sp., Kheraiceras cf. bullatus(Orbigny) and Kh. (Bomburites) sp. from the Lower Callov-ian (Bullatus Zone).

Some meters upward, also in the Malvariche section,ammonite assemblages were collected from the Lower Call-ovian (Gracilis Zone = Patina Zone, sensu Sequeiros, 1974).These show taphonomic reworking with neomorphized shells


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. Fuci-niceras 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,


together with inner molds, sometimes truncated, corroded,occasionally fragmented, and usually imbricate. Both innermolds and shells can occasionally be covered by Fe–Mncrusts. The assemblage is dominated by Phylloceratina [Phyl-loceras trifoliatum Neumayr, Holcophylloceras zignodi-anum (Orbigny), Calliphylloceras disputabile (Zittel) and Pty-chophylloceras flabellatum (Neumayr)], which reach the 60%.Macrocephallitinae as Macrocephalites gracilis (Spath)(Fig. 5E), and Macrocephalites? sp. along with Haplocer-atidae [Lissoceratoides jullieni (Douvillé)] are also abun-dant. Other groups as Hecticoceratinae (Hecticoceras (Cha-nasia) bannense Elmi (Fig. 5C), He. (Ch.) sp. andJeanneticeras? sp.), Reineckeiidae [Rehmannia (Re.) freii(Jeannet) sensu Cariou (1980) (Fig. 5D), Collotia oxyptycha(Neumayr)], Perisphinctidae (Choffatia waageni (Teis-seyre), Grossouvria sp., Parapatoceratinae, (Parapatocerastuberculatum (Baugier and Sauzé), Pa. sp.) and Oppeliinae(Oxycerites sp.) are also common. Middle Jurassic ammo-nites are scarcer in Prat Mayor section. Seyfried (1978)reported Spiroceras sp. and Nannolytoceras sp. from theUpper Bajocian, and we collected only two specimens (Hec-ticoceras (Ch.) sp. and Grossouvria sp., 214 m) which prob-ably represent the Lower Callovian (Gracilis Zone).

Oxfordian ammonite assemblages were recorded in 7 mof succession in the Prat Mayor section (237.5–244.5 m inFig. 2) at the top of nodular-limestone levels, sometimes brec-ciated. As usual in ammonitico rosso facies, ammonites arepreserved as inner moulds with complete phragmocone andincomplete body chambers. Sutures are poorly or not at allpreserved, indicative of relatively deep deposition (Fernández-López, 2000). No significant taphonomic size bias was noted,although the smaller ammonites are frequently lying oblique(even vertical) with respect to the stratification, especially atthe top of the strata. As a whole, Phylloceratina reach the37.5% (mainly Calliphylloceras and secondarily Sowerby-ceras) of the assemblage.

The Middle Oxfordian, Transversarium Zone, was regis-tered in a single horizon with the record of Calliphyllocerassilesiacum (Oppel), Ca. manfredi (Oppel), Sowerbyceras tor-tisulcatum (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

Pe. (Dichotomoceras) bifurcatoides Enay (Fig. 6A), Pe. (Di.)cf. bifurcatus (Quenstedt), Pe. (Dichotomosphinctes) cf. elisa-bethae (De Riaz) and a specimen of Pe. (Dichotomosphinc-tes) aff. ultimus, with atypical abundance of trifurcate ribs inthe body chamber, together with Calliphylloceras and Sow-erbyceras, which characterize the Bifurcatus Zone. The UpperOxfordian, Bimammatum Zone (or still the uppermost Bifur-catus Zone) was unsurely recorded in a horizon with Passen-dorferia (Passendorferia) cf. teresiformis (Brochwich-Lewinski), Pa. (Pa.) sp. and Trimarginites gr. trimarginatusOppel, just 50 cm below the first record of Subnebrodites inthe Planula Zone. Upwardly, four ammonite-bearing hori-zons, spaced within a thickness of 2.5 m, enabled the recog-nition 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), Orthos-phinctes sp. and abundant Phylloceratina (mainly Sowerbyc-eras).

Kimmeridgian ammonite assemblages in the Prat Mayorsection were registered from 246.4 to 260 m (Figs. 2 and 6).As in the underlying Oxfordian, the lithofacies is composedby nodular limestones with thicker and more brecciated lev-els. The Kimmeridgian succession has less, and more widelyspaced, ammonite-bearing horizons. Nevertheless, the ammo-nite mode of preservation is similar to that of the Oxfordian,although, due to the higher sedimentation rate, some speci-mens have lost the inner whorls (or have become flatteneddue 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 Sower-byceras.

Almost 2 m above the last record of the Planula Zone, thereis a horizon attributed to the lowermost Kimmeridgian(Platynota Zone?) based on the record of Sutneria gr. galar(Oppel), Streblites tenuilobatus (Oppel), Glochiceras (Lin-gulaticeras) gr. nudatum (Oppel)-lingulatum (Quenstedt), Gl.(Li.) sp., Aspidoceras sp., Orthosphinctes (Orthosphinctes)polygyratus (Reinecke) sensu Schairer morph. colubrinusOlóriz (Fig. 6F), Or. (Or.) sp, Or. (Lithacosphinctes) sp. andabundant Phylloceratina [So. silenum (Fontannes) as well as,secondarily, Ly. orsinii (Gemmelaro) and Ho. mediterra-neum (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 Carrascassection 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 Chicosection 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 Malvariche121 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. Arieticerasdisputabile (Fucini), PM.60.10, Domérien moyen, Zone à Algovianum, section de Prat Mayor 60 m. G. Emaciaticeras lottii Fucini, TC.100A.3, Domériensupérieur, Zone à Emaciatum, section de Tres Carrascas 1 m. H. E. levidorsatum Fucini, TC.40.1, Domérien supérieur, Zone à Emaciatum, section de TresCarrascas 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.


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 (Furlo-ceras) chelussi (Parisch and Viale), MC.180.8, Middle Toarcian, Gradata Zone, Morrón Chico section 1.8 m. B. G. speciosum (Janensch), MC.1000.1, UpperToarcian, Reynesi Zone, Morrón Chico section 10 m. C. Hecticoceras (Chanasia) bannense Elmi, MI.251.1, Lower Callovian, Gracilis Zone, Malvariche


Taramelliceras (Ta.) cf. trachinotum (Oppel) (Fig. 6E), Ta.(Ta.) sp., Glochiceras (Lingulaticeras) gr. crenosum (Quen-stedt), Pseudowaagenia aff. micropla (Oppel), Ataxioceras(Schneidia?) sp., and Ataxioceras sp., along with abundantSowerbyceras silenum (Fontannes), which dated the upper-most Platynota or the Strombecki Zone.

The remainder Lower Kimmeridgian (Strombecki orDivisum Zone) was recorded 2.6 m above, with the record ofNebrodites (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 preservedTa. (Ta.) gr. pugile (Neumayr), Discosphinctoides (Di.) aff.capillaceous (Dumortier) with Ho. mediterraneum (Neu-mayr) and So. silenum (Fontannes), which belong to theDivisum Zone.

The Upper Kimmeridgian was recognized in the top offour nodular-breccioids levels at 260 m in the Malvariche sec-tion (Figs. 2 and 6). Ammonites were badly preserved asreworked inner moulds with common fragmentation, imbri-cation and generalized disarticulation of body chambers andphragmocones along the septa. The recorded assemblage isdominated (more than 80%) by Phylloceratina [mainly So.loryi (Munier-Chalmas) morphs loryi and pseudosilenum, andfew Ho. polyholcum (Benecke)].

The four horizons studied were attributed to the BeckeriZone, with a similar ammonite assemblage composed, as morerelevant, of Hybonoticeras (Hy.) beckeri beckeri (Neumayr)(Fig. 6H), Hy. (Hy.) beckeri harpephorum (Neumayr)(Fig. 6G), Hy. (Hy.) gr. beckeri (Neumayr), Ta. (Ta.) pugilepugile (Neumayr), Ta. (Ta.) gr. pugile (Neumayr), Glochiceras(Lingulaticeras) sp., Shaireria cf. episa (Oppel), Aspi-doceras cf. sesquinodosum (Fontannes), Torquatisphinctes cf.laxus Olóriz, Biplisphinctes cf. uracensis Berckhemer andDiscosphinctoides (Discosphinctoides) sp. (Fig. 6)

No Tithonian ammonites were recorded in the Malvaricheor in the Prat Mayor section. Thus, the Upper Tithonian wasevidenced by the FAD of hyaline calpionellids, and the recordof the Crassicollaria Zone, at 295 m in the Malvariche and285 m in the Prat Mayor sections (Fig. 2). Finally, theTithonian/Berriasian boundary was approached by the bloomof large and isometric C. alpina (Calpionella Zone) at 330 min the Malvariche and 305 m in Prat Mayor sections.

6. Paleoenvironmental interpretation

The evolution of the Jurassic from the Malaguide at SierraEspuña is comparable to other sectors of the Tethyan paleo-

margins belonging to Internal and External Zones: the Sub-betic (S Spain, Vera, 1988), the Venetian Alps (N Italy, Zem-polich, 1993), the Apennines (Central Italy, Colacicchi et al.,1999), the Trapanese, (W Sicily, Catalano et al., 2002) or theGhomarids (N Africa, Maate, 1996). During the Jurassic itevolves as a passive margin, beginning with the pre-riftingstage, followed by the platform break-up of the rifting stage(starting from the Domerian, Lavinianum Zone), and finallythe 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 byoo-oncolitic limestones, sometimes breccioids, evolvingupwards to crinoidal limestones. These are interpreted asrestricted inner-shelf deposits of oolitic shoals, nearby algaland/or crinoidal meadows. Accordingly, the recorded faunasare solely abundant and well-diversified shallow-waterbenthos such as algae, crinoids, sponges, gastropods, bivalves(pectinids, ostreids and Lithiotis), brachiopods, solitary cor-als, echinoderms, and benthic foraminifers, among others.These benthic faunal assemblages are dominated by suspen-sion feeders, with little resedimentation processes, even lyingin living position (Lithiotis, corals). In such a context, therecorded upwardly thickening and coarsening parasequences(more developed in the Malvariche section; Fig. 3) may beinterpreted as upwardly shallowing cycles.

Above, the Domerian-Toarcian guide interval of alternat-ing yellowish marly/silty limestones (slightly nodular) withferruginous oolites and oncoids, records the beginning of therifting stage with the break-up of the platform (drowningunconformity). This event is linked to a tectonic pulse (activelistric faulting and tilting blocks), evidenced by the variablethicknesses and lithofacies among sections (Fig. 3) and thepresence of neptunian dykes (e.g. Morrón Chico section,Fig. 3). The restricted inner platform, where the underlyingoolitic limestones developed, may drown at relatively shal-low depth, leading to drastic reduction of carbonate produc-tivity with changes in current circulations and water chemis-try, probably with contribution of upwelling of eutrophicwater, rich in Fe–Mn oxi-hydroxides (influx of trophicresources and plankton coming from the open sea into theplatform). Thus, the faunal assemblages are alternativelydominated by benthos of low diversity (mainly brachiopods,echinoderms, bivalves), and, for the first time, pelagic assem-blages; stunted ammonites and belemnites of low diversity,with intense reworking, sometimes wrapped by ferruginouscentimetric-decimetric oncoids.

The interpreted depositional environment may be an openshelf, with variable depth, water chemistry and hydrodynam-ics, 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. gra-cilis (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. Phyma-toceras (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.


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, PlanulaZone, Prat Mayor section 243.7 m. C. Nebrodites (Nebrodites) gr. hospes (Neumayr), PM.252-1, Lower Kimmeridgian, Strombecki-Divisum? Zone, PratMayor section 252 m. D. Taramelliceras (Taramelliceras) subcallicerum (Gemmellaro), PM.252-2, Lower Kimmeridgian, Strombecki-Divisum? Zone, Prat


and tilting). Fig. 3 shows three tectonic blocks, limited byextensional faults. The intermediate block, which containsthe Tres Carrascas, Prat Mayor and Morrón Chico sections,tends to sink eastward, developing less thickness (“ammo-nitico rosso” condensed limestones) in the Tres Carrascas sec-tion and a thicker succession with yellowish marly/silty lime-stones containing ferruginous oolites and oncoids in theMorrón Chico section. The generalized sediment starvationcaused by the drowning of the platform led to a faunal accu-mulation as well as Fe–Mn oxi-hydroxides, which, togetherwith the few available sediments, may have been distributedby waves/currents to the active depocenter (eastern parts ofthe tilted blocks; Fig. 3), tending toward smoothing relief.

As in other Western Tethyan paleomargins, the tectonicsubsidence during the progressing rifting stage in the Dogger(probably already from the uppermost Liassic) caused anincipient half-graben system in the area (Fig. 7). Sierra Espuñaconstitutes a relatively subsident depocenter, in an outer shelfto upper-talus paleogeographic context. Thus, the sedimen-tation during this period is dominated by pelagic or hemipe-lagic sediments (gravity flows and periplatform ooze),enriched in chert, coming from the contribution of siliceousplanktonic organisms (radiolaria), especially in the upper part.Consequently, the recorded upwardly thickening and coars-ening parasequences, with stacking of thicker parasequencesabove reflected the general progradation of the platform.

Fauna is scarce in these well-stratified micritic/crinoidallimestones with chert. Benthos is represented almost exclu-sively by the disarticulated crinoid knuckles, which, togetherwith oolites, came from the shallower part of the platformtransported by gravity flows of sediment. Pelagic faunalassemblages are recorded only toward the upper part(Lower/Upper Bajocian and lowermost Callovian), in somecondensed horizons at the top of strata. They are dominatedby belemnites (often oriented, “belemnite battlefield” sensuDolyle and Mac Donald, 1993) and/or complete ammoniteswith body-chamber, but no septa preservation (mostly pelagicfree-swimmer forms such as Phylloceratids), which is inter-preted as in situ burial, in a relatively deep environment(Fernández-López, 2000). On the contrary, the recordedLower Callovian ammonites, which occur in relation to strati-graphic discontinuities, are truncated, corroded, fragmentedinner moulds that, at times, can hardly be distinguished from

mere intraclasts, together with epigenized shelly specimens;both are often domed by Fe–Mn laminae which are some-times concentric around of the nucleus. Similar cephalopodconcentrations appear in the Betic External Zones (Sub-betic). These have been interpreted (Sandoval and Checa,2002) as reworked assemblages formed on an irregular sub-strate subjected to energy pulses which would have led to theformation and repeated destruction of accumulation beds withdifferent microfacies.

As in many other sectors of the Tethyan paleomargin, thedrifting stage starts around the Dogger/Malm boundary,changing the generalized tectonics by thermal subsidence.This stresses the differentiation of the horst and graben sys-tem, and then the diversification of depositional environ-ments and facies (Figs. 2 and 7). During the Malm, the depo-sitional environment for the Malaguide in Sierra Espuña is amid-outer shelf that rises in some areas, becoming a distalpelagic swell with sedimentation of condensed ammoniticorosso, and related facies. In the study area, the condensedsedimentation linked to this raised sea-bottom started gradu-ally from the Middle Oxfordian (Fig. 2).

Among the two sections studied, a single tilted block ormore likely, as in the Liassic, two different blocks can beinterpreted, western side of which was relatively uplifted (situ-ation of the Malvariche section; Fig. 2) while the eastern sidewas relatively sunk (Prat Mayor; Fig. 2). Because of this, overthe interval with finely stratified marls and marly limestones,which are, consequently, thicker in the Prat Mayor section,the Middle–Upper Oxfordian to Kimmeridgian nodular-breccioid limestones were reduced and hiatal in the Malvar-iche section, while expanded and relatively with abundantresedimentation (pebbly mudstones) in the Prat Mayor sec-tion. Moreover, the relatively shallow depocenter at Malvar-iche presents only pelagic assemblages with ammonites inthe uppermost Kimmeridgian, when the eustatic sea level wasthe highest of the Upper Jurassic, while the relatively deeperdepocenter at Prat Mayor collected ammonites and otherpelagic faunas from the Middle Oxfordian.

In general, the Upper Jurassic ammonite assemblages aredominated by phylloceratids (especially by the eurythopic andubiquist genre Sowerbyceras), recorded only in condensednodular limestones, ammonitico rosso and related facies. Asusual 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 section249.4 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, BeckeriZone, Malvariche III section 1230–1250 m. H. Hybonoticeras (Hybonoticeras) beckeri beckeri (Neumayr), MIII.1270-1280-53, Upper Kimmeridgian, BeckeriZone, 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, Kimméridgieninférieur, Zone à Strombecki-Divisum?, section de Prat Mayor 252 m. D. Taramelliceras (Taramelliceras) subcallicerum (Gemmellaro), PM.252-2, Kimmé-ridgien 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 Schairermorph. 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.


inner moulds, mostly reworked; frequent loss of body-chambers and truncations incompatible with the stratifica-tion. In the nodular-brecciate facies, inner moulds of ammo-nites are often fragmented and imbricate.

Finally, at the end of the Jurassic the generalized thermalsubsidence tends to deepen the paleomargin, while the hugerelief caused by the horst and graben system is smoothed.Consequently, the area evolved to a basin in Lower Berria-sian (probably already from the uppermost Tithonian) withdeposition of periplatform limestones together with the localsedimentation by planktonic microfossils (calpionellids, fora-minifers, radiolarians, as well as algae).

7. Conclusions

A multidisciplinary study has enabled greater precision inupdating the biostratigraphic framework and the paleoenvi-ronmental interpretation of the Jurassic succession at SierraEspuña. This area, which is one of the bigger, better exposedand more fossiliferous Jurassic outcrops of the Malaguidedomain, can be considered a clue area to analyze the evolu-tion of the Internal Zones of the Betic Cordillera.

As a whole, ammonite biostratigraphic data from the Inter-nal Zones are scanty, and related only to the “Dorsal” andMalaguide domain such as the Sierra Espuña area. Particu-larly for this area, the previous biostratigraphic data, whichcomes from the 1960s and 1970s, need to be updated andrevised. Thus, three previously studied and two new Jurassicsections at Sierra Espuña were sampled, leading to a moreprecise biostratigraphic ammonite framework. Ammoniteassemblages have enabled the recognition of the Domerian,Lavinianum (Cornacaldense Subzone), Algovianum (Ragaz-zoni, Bertrandi, Accuratum and Levidorsatum Subzones) andEmaciatum (Solare and Elisa Subzones) Zones, the LowerToarcian, Polymorphum and Serpentinum Zones, the MiddleToarcian, Bifrons and Gradata Zones, the Upper Toarcian,Reynesi Zone, the uppermost Lower/Upper Bajocian, theLower Callovian (Bullatus and Gracilis Zones), the Middleand Upper Oxfordian (Transversarium, Bifurcatus, Bimam-matum and Planula Zones) and the Lower and Upper Kim-meridgian (Platynota, Strombecki, Divisum and BeckeriZones). Some of these zones and subzones are recognized, ordocumented with reported faunas, for the first time.

As a whole, benthic assemblages dominated during theLower Jurassic, while benthonic/planktonic assemblages

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 litho-faciès principal. M (mudstones), W (wackestones), P (packstones), G (grainstones). Légende des bioclastes Fig. 2.


developed within the Middle–Upper Jurassic. Ammonitetaphonomy reveals the abundance of reworked assemblageswith common truncation, imbrication and coating (by Fe–Mnoxides) of inner moulds or shells. Nevertheless, only occa-sionally during the Domerian–Lower Toarcian interval ofalternating yellowish marly/silty limestones the faunal con-densation mixed biostratigraphically recognizable horizons.The assemblages of ammonite faunas analyzed from theDomerian to the Kimmeridgian show a Mediterranean char-acter. Thus, the bio-chronostratigraphic zonal/subzonalscheme was applied, with minimal changes, for Mediterra-nean Province (Cariou and Hantzpergue, 1997).

The interpreted paleoenvironmental evolution of the Juras-sic Malaguide at Sierra Espuña appears to be similar, andcomparable in timing, to other perimediterranean Tethyanpaleomargins. It evolves as a passive margin, with develop-ment 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, thehorst–graven system begins and the area was drowned at con-siderable depth. Then, from the Lower Callovian to the MiddleOxfordian, the drifting stage started, emphasizing the horst–graven system with development of condensed nodular lime-stones in the raised sea-floor.

Acknowledgements

This research was economically co-financed by the re-search Projects BTE2001-3020, BTE2001-3029, BTE2000-0299 and BTE2003-01113 (Spanish Ministry of Science andTechnology) and Research Groups GR00-222, GV04B-629(Generalitat Valenciana) and RNM-178 (Junta de Andalucía).We are grateful to Professor A. Jiménez (University ofGranada) for Photograph assistance. We are also indebted toMr. D. Nesbitt for the revision of the English text.

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