3 Revista de la Sociedad Geológica de España 29 (1) ISSN (versión impresa): 0214-2708 ISSN (Internet): 2255-1379 LATE APTIAN CORALS FROM THE SOUTH IBERIAN SUB-BASIN (CRETACEOUS; EASTERN SPAIN) Corales del Aptiense superior de la subcuenca Suribérica (Cretácico; Este de España) Hannes Löser1 and Patrick Zell2 1 Estación Regional del Noroeste, Instituto de Geología, Universidad Nacional Autónoma de México, Blvd. Luis Donaldo Col. Los Arcos, Colosio S/N y Madrid, 83250 Hermosillo, Sonora, Mexico; [email protected] 2Institut für Geowissenschaften, Universität Heidelberg, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany; [email protected] Abstract: A small coral fauna from the Aptian Calizas con Rudistas del Caroch Formation 18 km NNE of Requena (Valencia) is described. A total of 21 species in 11 genera of the suborders Ar- cheocaeniina, Caryophylliina, Faviina, Meandrinina, Rhipidogyrina, Microsolenina, and Styli- nina are reported. For the genus Angelismilia the range of its stratigraphic distribution is extended. For the formerly monospecific genus Nudacolumastrea another two species are descri- bed. The studied fauna is typical for the Early Cretaceous; almost all species were indicated in the early Aptian, but less in the Albian or Cenomanian. Only one genus has a range beyond the Cenomanian. The fauna is dominated by plocoid colonies (genera Cryptocoenia, Holocystis and Nudacolumastrea; 13 species) whereas cerioid, flabelloid, meandrinoid, phaceloid, and solitary forms are subordinated. Palaeobiogeographic relationship exists with the lower Albian of Mont- mell Formation in East Iberia and various Mexican faunas of Aptian to Albian age. Key-words: Corals, Spain, Cretaceous, Taxonomy, Aptian, Calizas con Rudistas del Caroch For- mation. Resumen: Se describe una pequeña fauna de corales del Aptiense superior de las Calizas con Rudis- tas de la Formación Caroch. El afloramiento se sitúa a 18 km al NNE de Requena (Valencia). En total, se encontraron 21 especies en 11 géneros de los subórdenes Archeocaeniina, Caryophylliina, Faviina, Meandrinina, Rhipidogyrina, Microsolenina, y Stylinina. Para el género Angelismilia se extendió su rango estratigráfico. Por otro lado, para el género Nudacolumastrea, que estaba definido como mo- noespecifico, se describen dos especies más. La fauna estudiada es típica del Cretácico Inferior; casi todas las especies fueron atribuidas al Aptiense inferior, aunque se encontraron unas pocas caracte- rísticas del Albiense o Cenomaniense. Sólo un género tiene una distribución que sobrepasa el Ceno- maniense. La fauna esta dominada por colonias plocoides (género Cryptocoenia, Holocystis y Nudacolumastrea; 13 especies) mientras que las colonias cerioides, flabeloides, meandrinoides, fa- celoides, y corales solitarios son menos abundantes. Existen relaciones paleobiogeográficas con la fauna del Albiense inferior de la Formación Montmell en el este de Iberia y con otras faunas de Mé- xico de edad Aptiense y Albiense. Palabras claves: Corales, España, Cretácico, Taxonomía, Aptiense, Calizas con Rudistas de la Formación Caroch Löser, H. y Zell, P. (2016): Late Aptian corals from the South Iberian Sub-Basin (Cretaceous; Eastern Spain). Revista de la Sociedad Geológica de España, 29(1): 3-20. Revista de la Sociedad Geológica de España, 29(1), 2016 4 LATE APTIAN CoRALS The late Aptian is a critical time span for coral evolution. Pacific (Japan; Löser et al., 2002) and the Iberian Peninsula. Coral diversity increased gradually from the Hauterivian on to Apart from these areas, isolated faunas are known from nort- reach a diversity peak during the early Aptian (Löser, 2013b; hern Africa (Algeria; Masse and Chiki-Aouimeur, 1982), the Löser et al., 2013a), but the oceanic Anoxic Event 1a during Tatra Mts (Poland, Morycowa and Lefeld, 1966; for stratigra- the early Aptian and subsequent demise of the carbonate plat- phy see Masse and Uchman, 1997), and Greece (Löser, 2013a). forms limited coral growth and diversity substantially (Skelton Late Aptian coral fauna from the Iberian Peninsula are repor- and Gili, 2012). ted mainly from North and East Iberia by various authors (Al- Whereas early Aptian coral faunas were distributed world- loiteau, 1947; Schöllhorn, 1998; Tomás et al., 2008; wide, late Aptian coral faunas are limited to three larger areas: Bover-Arnal et al., 2012). Compared to the early Aptian, the the Western Hemisphere (Texas, USA; Puebla and Sonora, Me- total number of faunas is low. Here we present another late Ap- xico; Löser and Minor, 2007; Löser et al., 2013b), the Western tian coral fauna from the southern part of the Iberian Range. Fig. 1.- Map of the Iberian Peninsula with inset of the Embalse del Buseo region, at Chera village, Valencia province (a; simplified after Instituto Geográfico Nacional de España, 2014) and Aptian palaeogeographic map of Tethyan/eastern Atlantic regions (b; map based on Masse et al., 2000 and Skelton and Gili, 2012). The studied section is located on the eastern flank of the Pico Ropé peak at the Camino de Chelva (39°37'14.6"N 0°58'23.69"W). Revista de la Sociedad Geológica de España, 29(1), 2016 Hannes Löser and Patrick Zell 5 Study area The South Iberian sub-basin was formed during Late Juras- sic-Early Cretaceous times as a consequence of increased tec- tonic activity and block tectonics affecting the Iberian Basin situated in Central Spain (Van Wees and Stephenson, 1995). As a result of abrupt relative sea-level changes, the upper Barremian to upper Albian succession of the Iberian Basin reflects a large va- riety of depositional environments including fluvial, deltaic and transitional facies with intercalated marine wedges (e.g. Van Wees et al., 1998). The study area lies about 18 km NNE of Requena (Valencia), north of the village Chera, on the north-western margin of the Parque Natural Geológico de Chera-Sot de Chera (Fig. 1a). The studied section (Fig. 2) is situated on the eastern flank of the Pico Ropé peak at the Camino de Chelva. The Pico Ropé peak pro- vides an almost horizontal series of Barremian to Turonian well- exposed succession of about 300 m in thickness. In the Chera region, including the Pico Ropé locality, the Ap- tian interval is represented by deltaic and shallow marine sedi- ments of the Calizas con Rudistas del Caroch Formation, deposited on the western margin of the South Iberian sub-basin (García, 1977; Arias et al., 1979; Mas, 1981; Fig. 1b). The up- permost member of the formation, the Calizas del Buseo Mbr, is sandwiched between siliciclastic-dominated strata of the under- lying Arenas y Arcillas del Burgal Mbr (deltaic, Gargasian- Clansayesian; e.g., Vilas et al., 1982) and the overlying Calizas, Margas y Areniscas de Sacaras Fm (lagoonal, Albian; e.g., Meléndez and López-Gómez, 2003). Shallow marine fossils of the Calizas del Buseo Mbr, mainly rudistid bivalves of the genus Toucasia, oysters and benthic foraminifers, are abundant in several horizons of the succession at the Pico Ropé peak. Lithologies are dominated by organic- rich, thin- to medium bedded wacke- to grainstones. Three in- tercalated marly intervals rich in charcoal are present between the base and the middle part of the succession. The corals described here derive from a fossil-rich, 0.3 m- thick limestone with a bioclastic grainstone matrix of the Calizas del Buseo Mbr, immediately above 2 m-thick marls (Fig. 2). The diverse fauna represents an in situ record of a rudist, coral and brachiopod dominated biostrome; gastropods and oysters are less represented. High Corg. and siliciclastic contents as well as char- coal layers present throughout the entire succession indicate that the shallow marine environment under consideration was affected by phases of lowered oxygenation at the sea-floor and by a pro- nounced deltaic complex. The preservation is good; fossils are preserved three-dimensionally without evidence of deformation and erosion due to transportation. Gastropod shells are preserved; bivalves exhibit both their valves. Former aragonitic shell was re- crystallized to calcite. Assemblaged rudists (Polyconites verneuili Bayle in De Verneuil et al., 1860; Horiopleura lambertiDouvillé, 1889; Toucasia sp.) and microfossils in underlying (Salpingopo- rella muehlbergi Lorenz, 1902; Charentia cuvillieri Neumann, 1965) and overlying (Cuneolina parva Henson, 1948) beds indi- cate a late Aptian age for the horizon under consideration. Fig. 2.- Sedimentary column of the Lower Cretaceous at Pico Ropé peak. The coral fauna described here was collected from a fossili- ferous horizon from the upper part of the member (arrow). 1: conglomerate; 2: crossbedded conglomerate; 3: bedded sandstone; 4: crossbedded sandstone; 5: clay; 6: sandy limestone; 7: silty limestone; 8: crossbedded sandy limestone; 9: marl; 10: limestone. Revista de la Sociedad Geológica de España, 29(1), 2016 6 LATE APTIAN CoRALS Methods clmax, large lumen; clmin, small lumen; Coral specimens were cut and polished. Thin sections in crd, distance of calicular series; both transversal and longitudinal orientation were prepared crw, width of calicular series; where possible. Thin sections were scanned by passing light s, number of radial elements in adult calices; through them and using a flat bed scanner with an optical res- sd, density of radial elements. olution of 6,400 dpi. Scanned images were then transferred to Measurements in millimetres. The number of the measured grey scale bit maps. Their quality was amended by histogram specimen is indicated above the values. contrast manipulation