On the age of the lower part of Pseudozilian Beds in the region of Cerkno

Abstract

Basic volcanic and pyroclastic rocks in the Cerkno—Šebrelje region are underlain by an acid volcanic series. Their hanging wall is, however, different; at Trebenče and Novaki in the Cerkno region it consists of Pseudozilian graywacke and black clayey shale intercalated with reef limestone devoid of fossils. On the other hand a milky dolomite occurs at Šebrelje. The stratigraphic position of the latter is well defined by Diplopora annulata Schafhäutl indicating the Cordevol substage of Carnian stage. Hence follows, that the Pseudozilian beds at Cerkno and Diplopora-dolomite from Šebrelje are equivalent in time. The basic volcanic series from the Cerkno-Šebrelje region is easily recognizable and its top is designed to be a key horizon.