Palaeocurrent Pattern and Provenance of a Part of Gondwana Succession, Talchir Basin, Orissa

The Talchir Group and the Karharbari Formation including a Boulder Gravel Unit of Damuda Group had a predominant northerly palaeoflow with a radiating sediment dispersal pattern suggesting a transverse filling of the basin. In contrast, the Barakar sedimentation had a unidirectional northwesterly palaeoflow implying an axial filling. The sediments were largely derived from the Eastern Ghat source which occurs along the southern boundary of the basin. The Talchir Group represents a denudation phase of source area with declining relief manifested by a decreasing mean grain size and increasing complexity in the heavy mineral suite due to unroofing of low rank metamorphic rocks at the source. The Damuda Group represents a syn-and post-tectonic phase of sedimentation displaying differences in tectonic style manifested by source area uplift, basin subsidence and steepening of alluvial surface documented by upward increase in grain size, increased complexity in heavy minerals by exposure of high rank metamorphic rocks at source and post-tectonic drainage deflection towards northwest during Barakar sedimentation.