On the geology of central Badakhshan (north-east Afghanistan)

Abstract

Territory explored by the Italian geological expedition to Badakhshan during the summer of 1961 is described. The metamorphic rocks have been divided as follows: Faydzabad Gneiss, Qara Mughul Gneiss and Rabat Gneiss (pre-Devonian); Halqa Jar Amphibolite (from Devonian to Jurassic); black slates (undivided and probably of different ages). Besides these complexes there are several lithostratigraphic units, with semi-metamorphic facies. The igneous rocks are granite, granodiorite, quartz-diorite, and tonalite of three ages: Upper Permian-Lower Triassic, Upper Jurassic-Lower Cretaceous, and Tertiary. The sedimentary rocks, Cretaceous, Eocene, and Neogene, have been subdivided as follows: Shingan Formation, Qara Bulaq Formation, Mashad Limestone, Mohammad Aba Sandstone, Gazestan Formation, Baba Darwes Formation (marls and limestones with Cretaceous fossils), Kharakan Formation (with Eocene fossils), Kokcha Formation (Neogene), and Taluqan Gravel (Quaternary). Fluvio-glacial deposits, loess, alluvial and lacustrine deposits, landslides, and talus slopes, all Quaternary, are also present. Several formations border an old anticlinal core formed by the Faydzabad Gneiss. The anticline trends north-south. Groups of formations separated by unconformities are deformed to varying degrees of intensity.