Overview of the meso- to neoproterozoic evolution of the Vindhyan basin, central India

Despite its origin in a stable intracratonic basin, the Vindhyan Supergroup , central India, embodies tectonic-driven depositional cycles of various or ders. A marked change in sedimentation pattern was coupled with a transient plate-margin compression in the otherwise extensional regime. An unconform ity laterally correlatable with a conformity, that divides the Supergroup i n two sequences arose in consequence. Maximum flooding surfaces (MFS) withi n the sequences can generally be correlated with intrabasinal volcanism tha t drastically diminished through the initial rift to later sag stage of bas in evolution. Concomitantly with the change in tectonic milieu, paleoseismi c deformation structures and related deposits also became drastically reduc ed in scale, Nevertheless, metre- and decametre-scale depositional cycles c orrelate well with the subtle record of paleoseismicity, Intermittent tilti ng of the depositional substratum is demonstrable in systematic bed-dip cha nges in metre-scale fining upward depositional cycles in the rift stage. In the sag stage, it is reflected merely in consistent deflection of paleocur rent directions at the top of the decametre-scale parasequence sets. Toward s the top of the Supergroup, progressive thickening and decreasing frequenc y of parasequences indicates a declining rate of basin subsidence. Prograda tion, despite punctuation, thus resulted in basin-filling. (C) 2001 Elsevie r Science B.V. All rights reserved.