Palaeoenvironmental Reconstruction of the Early Proterozoic Kolhan Siliciclastic Rocks, Keonjhar District, Orissa, India

The early Proterozoic Kolhan sihciclastrc rocks of the Kolhan Group (c. 2100 Ma) exhibit extensive-development of thickly bedded sandstone, impersistent conglomerate and siltstone. Six major lithofacies were recognised, viz, granular lag (GLA), granular sandstone (GSD), sheet sandstone (SSD). parallel laminated sandstone (PLSD), rippled sandstone (RSD) and thinly laminated siltstone-sandstone (TLSD). The vertical and lateral arrangement of lithofacies with their general finmg upward sequence is interpreted to reflect superimposition of retrograding shoreline on the earlier, prograding humid alluvial fan-sandflat complex and can be comparable with the present day storm-induced sedimentation on the NW Atlantic shelf.