Petrogeochemical Characteristics of Late Devonian Metagabbro-Dolerites of the Kara Astrobleme, Nenets Autonomous District, Russia

Abstract

The paper presents the results of detailed petrographic and petrogeochemical studies of metagabbro-dolerites from the central part of the Kara astrobleme. The data obtained made it possible to narrow the petrographic diversity of the rocks to two varieties: quartz-free metagabbro-dolerites and quartz-bearing metagabbro-dolerites, which were formed through differentiation of a single magmatic melt. The geochemical features of the rocks indicate the heterogeneity of the magma-generating source. The rock-forming minerals of the quartz-free and quartz-bearing metagabbro-dolerites are characterized by the presence of planar elements of the low and middle stages of impact metamorphism.