Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

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Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

A review of the stratigraphic distribution of ammonoid species in the Lower Cretaceous (Hauterivian-Albian) of the Maestrat Basin (E Spain) was carried out. The specimens were mainly collected in the field by us and are stored in university or museum collections. Speci­mens from private collections and figured in the literature were also studied. We recognized 73 species that are distributed, in accordance with the latest version of the standard Mediterranean ammonite zonation for the Lower Cretaceous, in 14 ammonite zones: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Lower Hauterivian); Pseudothurmannia ohmi (Upper Hauterivian); Imerites giraudi (Upper Barremian); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Lower Aptian); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani (Upper Aptian); Leymeriella tardefurcata and Douvilleiceras mammillatum (Lower Albian). The recognition of these biozones allows a precise age calibration of the Maestrat Basin’s lithostatigraphic units that contain ammonoids as well as an associated indirect age calibration of the formations without ammonoids. Consequently, this report provides an updated, comprehensive and precise biostratigraphic framework, which aims to become a reference for the analysis of the Lower Cretaceous strata of the Maestrat Basin. The results are also relevant for the analysis of coeval ammonite-bearing sedimentary successions found in other Tethyan basins.En este trabajo se ha realizado una revisión detallada de la distribución estratigráfica de las especies de ammonoideos del Cretácico infe­rior de la Cuenca del Maestrazgo (Este de España). Los ejemplares recolectados, principalmente por los autores, han sido depositados en co­lecciones universitarias y museísticas. Además hemos estudiado los ejemplares de colecciones privadas y figurados en la literatura. Hemos reconocido 73 especies que se distribuyen, siguiendo la última versión de la biozonación de ammonites mediterránea estándar del Cretácico inferior, en 14 zonas de ammonoideos: Acanthodiscus radiatus, Crioceratites loryi, Lyticoceras nodosoplicatum (Hauteriviense inferior); Pseudothurmannia ohmi (Hauteriviense superior); Imerites giraudi (Barremiense superior); Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, Dufrenoyia furcata (Aptiense inferior); Epicheloniceras martini, Parahoplites melchioris, Acanthohoplites nolani (Aptiense superior); Leymeriella tardefurcata y Douvilleiceras mammillatum (Albiense inferior). El reconocimiento de estas biozonas permite precisar la edad de las unidades litoestratigráficas que contienen ammonites y también una calibración indirecta de las formaciones que no contienen ammonites. En consecuencia este trabajo proporciona un marco bioestratigráfico actualizado, exhaustivo y preciso que pretende ser una referencia para el análisis estratigráfico del Cretácico inferior de la Cuenca del Maestrazgo. Los resultados obtenidos son también relevantes para el análisis de las sucesiones sedimentarias coetáneas con ammonites existentes en otras cuencas de Tetis