La Formación vulcanosedimentaria del Castro (Ordovícico-Silúrico) en el Cabo Peñas (Zona Cantábrica, NO España)

Abstract

This work deals with the stratigraphies and palaeontological study of the vulcanosedimentary Castro Formation in its type locality,: close to Cabo Peñas (Asturias, Cantabrian Zone). The formation consists of three members: a lower member of alternating volcanoclastic and sedimentary rocks, a middle member, mostly basaltic, and an essentially upper calcareous member (Viodo Mb.). On the basis of the palaeontological data, and the preliminary results from the correlation with Cabo Vidrias section (west of Cabo Peñas), a Middle Ordovician age is established for the lower member. The Viodo Mb. is Lower Silurian in age as shown by an abundant fossiliferous content. So far, fossils supporting the occurrence of the Upper Ordovician have not been found, although it could be represented in the middle member of the formation