Sedimentary Structures and Paleocurrent Analysis of the Barakar Sandstone in Chirimiri (Kurasja) Coalfield, Madhya Pradesh

Abstract The Barakar sandstone of Chirimiri (Kurasia) coalfield includes complete or truncated sedimentary cycles, some of which commence with pebbly gritty coarse sandstone and, fining upwards through coarse cross bedded sandstone, end up with carbonaceous siltstone or coal seam. Among the primary depositional structures, ripple drift, trough and tabular cross bedded sets and cosets are common. These structures have been described from the genetic and hydrodynamic viewpoints. Erosional structures occurring in the sandstone include channels, scour-and-fill, potholes and flute casts. A paleocurrent analysis based on 88 cross bedding azimuths reveals the preponderance of two depositional current systems - the main current system which flowed from southeast, and a tributary system flowing from east-northeast. An increase in cross bedding variability at higher sampling levels reflects the meandering behaviour of depositing currents. A sedimentary analysis of the sandstone sequence suggests that the Barakar sedimentation in this coalfield was controlled, perhaps right from the beginning, by periodic tectonic uplifts of the granitoid landmass located to the east and southeast. It is suggested each tectonic uplift resulted in the deposition of a fining-upwards fluvial cycle.