Provenance, Tectonic Setting and Climatic Conditions during Lower Permian Barakar Sedimentation in the Mand Gondwana Basin, India - A Petrographic Approach

The present study is an attempt to determine the provenance characteristics, tectonic setting and climatic conditions prevailing at time of sedimentation of Barakar Formation (Lower Permian). The Barakar Formation is chiefly composed of sandstones with subordinate amount of shales, carbonaceous shales and coal seams. The average composition of Barakar sandstones is quartz 57.93 to 82.42% (42.35 to 75.45% monocrystalline and 2.99 to 37.16% polycrystalline quartz), feldspar 3.0 to 15.16% and rock fragments upto 4.95%. These sandstones have been classified as sub-arkose and sub-litharenites types. The modal composition indicates that component minerals of these sandstones have been derived from craton interior and recycled orogenic belt, where different types of granitic, gneissic, sedimentary and metasedimentary rocks were exposed. The dominance of K-feldspar over plagioclase in these rock samples suggests that the source rocks were exposed for long duration of time and subjected to intense weathering under humid climatic conditions.