Caracterización geológica de los afloramientos de El Pimpollar, extremo nororiental de la Zona Surportuguesa

Abstract

Two volcanic units can be distinguished in the “El Pimpollar” outcrop (eastern South-Portuguese Zone). The Lower Unit is composed mainly of submarine dacites and andesites, with some subordinated basalts and trachyandesites. The Upper Unit is composed of massive rhyolites, with volcano-sedimentary and volcanoclastic deposits towards the base. Radiolaritic sediments interbeded with the andesites and dacites show that these volcanic rocks extruded in a relatively deep marine basin. The upper part and top of the Lower Volcanit Unit includes some diamictic layers related with masstransport processes. Some of these diamictic layers contain limestone pebbles and blocks with middle Visean microfossils. These sedimentary deposits mark possibly the beginning of a tectonic event that was responsible for the destruction of a carbonate platform, and for severe changes in the tecto-sedimentary environment