摘要
Detailed sedimentological analysis of the Pokaran Boulder Bed,representing the most basal unit of the Neoproterozoic-Lower Cambrian Marwar Supergroup,clearly indicates its glacial origin.The glacial sediments are interpreted as an ice-contact submarine fan deposit.Based on the detrital and inherited zircon population of the Marwar Supergroup sediments and interlayered pyroclastic deposits,a Marinoan cryochron of the Cryogenian Period is envisaged for the Pokaran Boulder Bed.The well-preserved Ediacaran elements in the post-glacial sedimentary succession also support a Cryogenian to Early Cambrian age of the Marwar Supergroup.The glacial deposition at the base of the Marwar Supergroup strengthens the regional correlation between the studied sediments with the Lesser Himalayan Blaini-Krol-Tal sediments and the Haqf Supergroup of Oman.The available zircon ages and paleomagnetic data of the Malani Igneous suite,along with the Marinoan glacial deposits,detrital zircon ages,and Ediacaran fossil elements of the Marwar Supergroup add significant information to the Neoproterozoic Earth history.
