A PALEOMAGNETIC VIEW OF THE VINDHYANCHAL BASIN, INDIA

The cratonic blocks of East Gondwana represent an important element of Proterozoic paleogeographic reconstructions and tectonic studies. This is particularly true for the Proterozoic, where a lack of high quality data inhibits paleogeographic reconstructions. The Indian craton represents a crucial piece to the puzzles of the configuration of the proposed Rodinia supercontinent, as well as the subsequent assembly of Gondwana after the Neoproterozoic breakup of Rodinia. In order to develop this high quality data, precise paleomagnetic studies of sedimentary rocks from the <1650 Ma Vindhyan system in Rajasthan and Madhya Pradesh, India are being conducted. These samples include extensive red bed sandstones and shales from the Bhander and Rewa groups, as well as limestone from various formations in both the Upper and Lower Vindhyan sequence and the so-called porcellanites. Previous paleomagnetic studies on these units have been conducted on parts of this section, but data quality was not necessarily up to today's standards and lacked field tests (e.g. fold, conglomerate and reversal). Age control on the magnetizations will be provided from dating of ash beds found in some of the units sampled as well as from dating the Majhgawan kimberlite that intrudes the Kaimur sandstone. The Majhgawan kimberlite yields identical directions to the Bhander-Rewa sequence. We will present the preliminary paleomagnetic and geochronologic data from this project.