Pattern of sedimentation during the Late Paleozoic, Gondwanaland glaciation: An example from the Talchir Formation, Satpura Gondwana basin, central India

摘要

The Talchir Formation of Permian age is the lowermost lithostratigraphic unit of the Indian Gondwana successions preserving a record of the Late Paleozoic glaciation that affected the whole Gondwanaland.The formation unconformably overlies the Precambrian basement in all the Gondwana basins of India,and marks initiation of sedimentation after a long hiatus since the Pro- terozoic.The Talchir Formation of the Satpura Gondwana basin of central India shows features diagnostic of deposition under glacial regime such as the presence of diamictites,boulder pavements, bedding plane striation,faceted/striated gravels,bullet-shaped clasts,dropstone,cryoturbation, etc.The Talchir strata of the Satpura basin,in addition to tidal signatures,contain marine bivalve and trace fossils.A proglacial marine environment is thus inferred for their deposition.The dominant lithologies are conglomerate,pebbly sandstone,sandstone and shale with little limestone, which can be classi???ed into the following major facies:matrix-supported conglomerate,