Madhumita PANJA¹, Gopal CHAKRABARTI² & Debasish SHOME^3
1Department of Geological Sciences, Jadavpur University, Kolkata 700032, India.
²Education Directorate, Government of West Bengal, India, Kolkata 700091, India, gl_chak@yahoo.co.in
³Department of Geological Sciences, Jadavpur University, Kolkata 700032, India.

DEPOSITIONAL SYSTEM OF AN OPEN COAST TIDALFLAT - AN EXAMPLE FROM PALEOPROTEROZOIC VEMPALLE FORMATION, CUDDAPAH BASIN, INDIA

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The sedimentological study in the Paleoproterozoic Vempalle Formation of the Cuddapah Basin, in and around Gandi, (14°20'2.51"N, 78°28'52.96"E), Vempalle town (14°21'27.74"N, 78°28'16.46"E; 14°21'28.86"N, 78°27'46.63"E) and Nandemandalam village (14°24'33.84"N, 78°31'39.22"E) reveals three major facies associations viz. supratidal facies association consisting of cross-bedded gritty quartzite facies, heterolithic facies and laminate facies; intertidal facies association consisting of red shale, lime-mudstone, ooliticgrainstone, and domalstromatolite facies whereas deeper intertidal environments are locally dominated by columnar stromatolite, massive dolomite and intraformational carbonate conglomerate and subtidal facies association consisting of conical stromatolite facies. Facies association and associated syn-sedimentary deformation structures, stromatolite morphology and microfabric clearly demonstrate that the Vempalle Formation in the study area was deposited in an open coast tidalflat having mixed influence of waves and tides, the storm dominated depositional processes marked by accretionary deposition of HCS and the scarce influence of tides in depositing sand.