HONING INDIA'S PALEOPROTEROZOIC PALEOGEOGRAPHY; A STUDY OF DHARWAR MAFIC DYKE SWARMS

In attempting to reconfigure past continental configurations, it is important to seek regions where unaltered sequences of igneous and sedimentary Precambrian rocks are preserved. Peninsular India is one such region and previous work indicates a high potential for generating useful data from India that can be used in conjunction with other regions to produce paleogeographic maps for the Precambrian. The Indian subcontinent is central to many Precambrian paleogeographic reconstructions including the supercontinents of Columbia and Rodinia. Within the Dharwar craton, and to the south and west of the Cuddapah Basin, mafic dyke swarms intrude the older Archean granites and gneisses. The mafic dykes are oriented in a variety of directions ranging from E-W, WNW-NW, NE-ENE, and N-S. French and Heaman (2010) used precise U-Pb dating and determined the emplacement ages for some of the dykes to be 2369-2365 Ma, 2221-2209 Ma, and 2181-2177 Ma. We targeted dyke swarms located near Hassan, Tiptur and Kunigal (west of Bangalore) along with a very dense concentration of dykes in the Tirupati-Chitoor region (E-NE of Bangalore). We present preliminary results from these dykes along with a review of recently published geochronological and paleomagnetic results from Proterozoic dykes elsewhere in India.