Geology of Eastern Ghats in Andhra Pradesh

Abstract

The lithology, structure, metamorphism and stratigraphy of the granite gneisses, charnockite series, khondalite series and granites occurring in the Eastern Ghats of Andhra Pradesh are described. The granite gneisses consist of the garnetiferous granite gneiss, the grey granite gneiss and porphyritic granite gneiss. The charnockite series consists of granite, diorite, gabbro, norite, amphibolite and pyroxenite. The khondalite series comprises gneisses, schists, quaitzites, and granulites, metamorphosed from argillaceous, arenaceous and calcareous sediments. The granites include the pink granites and pegmatites. The formations are highly folded with thrusts and strike slip faults. The granite gneisses, charnockite series and khondalite series are metamorphosed to the granulite facies, with a few members in the amphibolite facies and occasional members in the eclogite facies. Some granite gneisses are the oldest rocks present, and others contemporaneous with charnockite series, which are themselves older than or contemporaneous with the khondalite series. The pink granites and pegmatites are the youngest rocks of the region.