Depositional history of the Upper Vindhyan succession, central India: Time constraints from Pb-Pb isochron ages of its carbonate components

Age of the upper sedimentary units (Rewa and Bhander Groups) of the largest Proterozoic Vindhyan Basin in central India has so far been considered to be close to 650 Ma (late Neoproterozoic) based on collective proxy dates in the absence of direct isotopic dates. A drastic upward revision of this age by more than 300 Ma has very recently been proposed from the similarity of the paleomagnetic directions in these units with those of the 1070 Ma old Majhgawan kimberlite intrusion into their basal parts, and the presence of detrital zircons not younger than 1020 Ma. We report now Pb-Pb isochron ages of 908 ± 72 Ma, 866 ± 180 Ma and 1073 ± 210 Ma for the three distinct carbonate horizons, Bhander-, Balwan- and Lakheri Limestones, respectively as independent and direct evidence on the age of the Upper Vindhyan succession. The consistency of the three ages close to 900 Ma provides a strong support for the proposed shift on the timing and duration of sedimentation in the Upper Vindhyan sequence.