MANTLE-PLUME CONTROLLED STRATIGRAPHY AND SEDIMENT DISPERSIONS OF THE EAST COAST OF INDIA DURING MESOZOIC RIFTING

Using an integrative and robust subsurface-dataset, various stratigraphic units, ranging in age from Mesozoic to present, are correlated and mapped along the entire east coast of India. Emphasis was given to understand continent-wide controls of basin evolution during East Gondwana rifting. Mesozoic sedimentary packages thin towards northeast, an area that was part of a location in East Gondwana experiencing extensive Mesozoic magmatism. Synrift strata (Lower Jurassic to Lower Cretaceous) are also missing in this area, indicating that the area was a paleo-high likely linked to mantle-plume related uplift. During Cenozoic, sediment depocenter shifted to northeast because of the combined influence of post-plume subsidence of the lithosphere and a huge supply of sediments from the newly uplifted Himalaya.

This study suggests that the existence of a large mantle plume (Kerguelen-Heard plume) in East Gondwana, as hypothesized by some early workers, exerted first order control in pre- to post-rift sedimentation style of eastern India. Because of the evolution of this plume, sediment transport direction switched between northward and southward during Jurassic, as revealed by paleocurrent analysis of dipmeter data, and major sediment-depocenter shifted from southwest during Mesozoic to northeast during Cenozoic. Synrift hydrocarbon plays are likely developed better in the southwest part of the study area.