Hummocky Cross-Stratification in Barakar Formation, Ramgarh Coalfield, Bihar

Sequence of moderately sorted siltstone to coarse grained sandstone containing abundant hummocky cross-stratified and swaley cross-stratified bedding has been described from five stratigraphic levels in a part of Barakar Formation, along the Damodar river, Ramgarh coalfield, Bihar. Scour and drape type and non-erosional based growing bed-forms, both types of hummocky crossstratification have been observed. The large dimension of hummocks, upsweeping of laminae, sigmoidal nature, broadly undulating erosive and flat base, draping and also the presence of tide influenced associated sedimentary structures, high sulphur and phosphorous content in the coal seams, high vitrinite content in the coal, absence of fining upward sequence, clay mineralogy, high concentration of chromium, similarities in trace element content with that of Assam coalfieds and presence of marine microfossils probably indicate that the observed part of Barakar Formation were deposited in an estuarine to marginal marine environment, Water depth was probably of the order of 1-30 m.