Lower Gondwana sedimentation in Saharjuri coalfield, Bihar, India

Abstract A sedimentary-tectonic environmental analysis of the continental lower Gondwana (upper Carboniferous and Permian) sediments indicates that deposition of glaciofluvial and glaciolacustrine sediments in Talchir (upper Carboniferous) times took place in elongated natural depressions between parallel ridges. In Barakar (Permian) times, relief was more rugged and Barakar sediments generally represent piedmont alluvial sheets. Five coal seams, ranging in thickness from 2 feet to 20 feet, are associated with typical continental sediments. A prominent sedimentary cycle (channel sandstone-laminated shale-coal-carbonaceous shale-kaolinitic shale-laminated shale) has been explained by a tectono-geomorphic cycle. Coal appears to have originated by in situ growth from decayed vegetation. Adjoining basins, big and small, were essentially unconnected in Barakar times and show dissimilar sedimentary and tectonic history.