Dharwar Craton

Abstract

Indian shield consists five major Archean-Paleoproterozoic cratons, e.g. Dhrawar, Bastar, Singhbhum, Bundelkhand and Aravalli. Out of these, the Dharwar craton is one of the oldest and the largest, covering almost entire terrain of southern India. It can be divided into three geotectonic blocks; western and eastern Dharwar cratons and southern granulite terrain. All of these blocks exhibit distinct geologic, tectonostratigraphic, magmatic and geochronologic characters, which are well reflected in the regional geophysical fields. Gravity anomalies are largely negative, reaching as low as -120 mGal. Heat flow is also quite low over this craton compared to most of those cratons located in the north. In its western part, the lithosphere is quite thick (185 km). Numerous studies have now indicated that the present-day continental crust below this craton, may have evolved through arc magmatism and accretion, rifting, continent-continent collision, suturing and basaltic magma extrusion. Inner parts of this craton may have been rifting as late as in Gondwana period, challenging the wide held belief of cratonic instability.