Mapping of tectonic corridors through hidden parts of the Greater Dharwar Terrane, Southern India

Abstract

The Dharwar craton (India) has been divided into western and eastern domains by a tectonic boundary between the Closepet granite and Chitradurga schist belt. It has been noted that only the central portion of the Dharwar craton is exposed; its northern projection is buried beneath the Deccan traps and its southern margin merges with a high grade metamorphic transition of late Archean age. Resolution of structure and extent of the Greater Dharwar Terrane (GDT) beneath its northern and southern end, the Deccan traps, metamorphic transition zone, and Cuddapah basin thus remains unsolved. Results of deep geophysical probings have been examined along with associated geological and tectonic data. The analysis leads to: (a) delineation of palaeo-accretionary corridors extending under the Deccan trap cover, along which, two damaging stable continental region earthquakes (Koyna and Latur) occurred ( Veeraswamy and Raval, 2005), (b) it is seen that the Latur earthquake seem to lies within an unsuspected tectonic corridor which bifurcates the eastern Dharwar craton (EDC) into eastern Dharwar craton-1 and eastern Dharwar craton-2 passing through the Cuddapah basin, (c) possibility of the Palghat–Cauvery shear zone connecting to the 2.5 Ga metamorphic Karimnagar granulite belt through the interface between Napier (NC) and Rayner (RC) complexes of East Antarctica, and (d) the indication that the Bavali–Moyar, Bhavani–Mettur and Palghat–Cauvery shear zones form the southern margins of the western Dharwar craton, eastern Dharwar craton-1 and eastern Dharwar craton-2 respectively.