Fauna de Ammonites del tránsito complejo Urgoniano-Flysch negro entre Gernika y Deba (Albiense medio y superior, región Vascocantábrica Septentrional)

Abstract

Ammomte fauna from the Urgonian-Black Flysch transition complex between Gernika and Deba (Middle and Upper Albian, North Basque-Cantabrian Region).

The fauna of ammonites from the Urgonian and Supraurgonian (Black Flysch) complexes, between Gemika and Deba (Bizkaia and Gipuzkoa), is described. The Urgonian consist of limestone horsts and lutite troughs separated by active faults. Limestones are mainly rudist and coral micrites and the adjacent lutites enclose resedimented limestone megabreccias and quartz conglomerates. The Black Flysch is made up of thick sandy turbidites passing laterally to lutites and thin sandy turbidites and to thoroughly bioturbated sandstones. Two ammomle associations are distinguished from these units, corresponding to the Middle Albian (Urgoman complex) and to the early Upper Albian (Black Flysch complex). Species of the following genera are described within the first association (Middle Albian): Phylloceras, Anagaudryceras, Kossmatella, Tetragonites, Puzosia, Desmoceras, Lyeiiceras, Tegoceros, Neophlycticeras, Metahamites and Hamites . The second association (early Upper Albian) includes species of: Kossmatella, Puzosia, Hysteroceras and Mortoniceras. The fauna described is cosmopolitan and its constituent taxa show atlantic as well as tethyan characteristics.