Rasgos estratigráficos de la sucesión del Ordovícico Superior en Portilla de Luna (Zona Cantábrica, noroeste de España)

Abstract

Upper Ordovician rocks have been characterized for the first time in the Cantabrian Zone of the Hesperian Massif. The sequence consists of a lower siliciclastic unit of Caradoc-(‘basal Ashgill age developed as an alternation of shales, siltstones and sandstones, overlain by an upper unit of fossiliferous limestones with marly intercalations, of pre-Hirnantian (mainly Cautleyan-Rawtheyan) age. Ashgill fossils are fairly abundant in the limestone unit, and there have been identified brachiopods of the «Nicolella fauna», echinoderms of the «Heliocrinites fauna» and trilobites of the Qvalocephalus biofacies