Sources of Cement in Barakar Sandstones from Umrer Coalfield, Nagpur

Two broad categories of silica sources, causing silica cementation in Barakar sandstones from Umrer coalfield identified are: (1) external source and (2) internal source. In first category, silica is inferred to have been derived from associated shale and siltstone beds. The silica recovered from the limited compaction as well as through vugs and solution openings generated by intrastratal solution activity represents the second category. The ferruginous cement has resulted from weathering processes while pedogenic processes are responsible for carbonate cementation.