EVOLUTION OF THE MESOZOIC SEDIMENTARY BASINS ON THE EAST COAST OF INDIA

The stratigraphy, structure, and tectonics of the Cauvery, Godavari-Krishna, Palar, and Mahanadi Basins located on the east coast of India are considered on the basis of up-to-date surface and subsurface data with particular reference to their evolution during the Mesozoic Era.The sediments exposed in the respective basins are limited to their western and northern borders and represent a relatively smaller stratigraphic interval as compared to the sequence known to be present in the subsurface.Each of these basins is bordered to the west by down-to-the-basin faults. The structural style and recognisable regional trends of the respective basins parallel those of the Eastern Ghats which were largely responsible for their evolution during the Jurassic period. The basin morphology during Late Jurassic comprised horsts and grabens formed due to tensional forces leading to basin subsidence with localised uplifts. The close of the Mesozoic was marked by a regional easterly regression and basinal tilt and an almost complete cessation of horst and graben development and the formation of an essentially monoclinal post-Mesozoic sedimentary cover.A close similarity between the Mesozoic sedimentary basins on the east coast of India and those on the west coast of Australia is marked inasmuch as their tectonic setting, structural style, lithologic suites and faunal and palynological assemblages are concerned. The study broadly indicates that during the Late Jurassic-Early Cretaceous period the basins on the east coast of India were bordered by land masses similar to those postulated to the west of the West Australian basins.