Lower Cambrian Archeocyatha of Navalcastano (Sierra Morena, Cordoba, Spain); systematics and biostratigraphy

The finding of archaeocyaths in the Navalcastano locality occurred in 1971, followed by collection of abundant material with archaeocyaths in 1973, which was preliminarily studied and included in the Doctoral Thesis of one the authors (A. P.). All the material collected in 1973, 2006 and 2007 is described in the present paper, together with analyses of the carbonate microfacies in which they were found, the proposal of a stratigraphic distribution of the described taxa and their correlation with other Spanish, SW Gondwanan and Siberian Plate localities. Twenty-two archaeocyathan taxa are described and figured, among them a new species, Nochoroicyathus castanensis sp. nov. The association of taxa found in Navalcastano is made up of the genera Anthomorpha, Cordobicyathus, Coscinocyathus, Dokidocyathus, Erismacoscinus, Fallocyathus?, Morenicyathus, Neoloculicyathus, Nochoroicyathus, Okulitchicyathus, Protopharetra, Rotundocyathus, Taylorcyathus and Urcyathus. The presence of the genus Anthomorpha in these materials allows us to assign the assemblage to the Late Ovetian, which is characteristic of Zones VI and VII in Spain, and equivalent to Botoman 1 and 2 in Siberia, according to the Russian zonation (PEREJON, MORENO-EIRIS & MENENDEZ, 2006). In accordance with the whole set of identified genera, we assign the archaeocyathan assemblage from Navalcastano to the Spanish Archaeocyathan Zone VI, the lowest level for the appearance of Anthomorpha in the Iberian Peninsula and SW Gondwana. Bol. R. Soc. Esp. Hist. Nat. Sec. Geol., 102 (1-4), 2008. i. Unidad inferior azoica, pizarroso-arenosovolcanica CA1p, CA1v ii. Unidad detritico-conglomeratica CA1s iii. Unidad carbonatada fosilifera CA1c iv. Unidad superior detritica fosilifera CA1 En el entorno de la finca las estructuras tectonicas, de direccion aproximada E-O, estan formadas por un anticlinal fallado y desplazado, con materiales de la Unidad detritico-conglomeratica, sobre la que se dispone la Unidad carbonatica fosilifera que mas al sur forma un sinclinal. Esta unidad carbonatica esta constituida por dolomias y calizas que alternan con areniscas, margas, pizarras y algunos materiales volcanicos. En la Memoria de la Hoja geologica solo se cita una localidad con arqueociatos “balcon [sic] de las Ninas” en la carretera que une la de Cordoba-Villavicosa con la de Cordoba-Santa Maria de Trassierra, pasando por Las Ermitas. CARBONELL (1940) resume los datos sobre las localidades con arqueociatos recopilados durante sus trabajos de campo por el norte de la 94 A. PEREJON, E. MORENO-EIRIS y S. MENENDEZ Bol. R. Soc. Esp. Hist. Nat. Sec. Geol., 102 (1-4), 2008. Fig. 1.–Mapa de situacion de Navalcastano (Cordoba) sobre el mapa de las Zonas de Lotze, modificado por SAN JOSE LANCHA, M. A. DE (2003: Fig. 3). –Location map of Navalcastano (Cordoba) over the map with Lotze’s Zones, modified by SAN JOSE LANCHA, M. A. DE (2003: Fig. 3). ZONA CANTABRICA ZONA ASTUROCCIDENTAL-LEONESA