Provenance of glauconitic sandstones of kheinjua formation of Semri Group, Son valley, central India: Evidence for uplift of a rifted continental margin basin

The paper embodies results of petrofacies, detrital mineralogy, texture and diagenetic aspects of glauconitic sandstones of Kheinjua Formation of Vindhyan Basin, Son valley. These glauconitic sandstones consisting of various types of quartz, feldspar, rock fragments, mica and a suite of heavy minerals, are medium to very fine grained, and well to moderately well sorted. These sediments including glauconite grains are generally subangular to subrounded with a few grains being well rounded. These sandstones are well compacted and dominated by interpenetrative contacts and are mainly cemented by iron cement with small amount of glauconite and silica cement. The existing optical porosity has developed due to dissolution of iron cement, feldspar and rock fragments. These observations suggest progressive compaction, which initiated at the sediment-water interface and continued till deep burial diagenesis in a rapidly subsiding basin. The plots of petrofacies in Qt-F-L, Qm-F-Lt, Qp-Lvm-Lsm and Qm-P-K ternary diagrams suggest mainly basement uplift source (craton interior) in a rifted continental margin basin setting, which has also received sediment input from recycled orogen provenance. The plot of various quartz types on diamond diagram after Basu et al. (1975) reflects derivation of the sediments from the plutonic and middle to high-rank metamorphic terrains. Besides, Lower part of the Semri Group, the most probable provenance of these sandstones is Bijawar metasedimentary and Bundelkhand Gneissic complexes, which bordered the basin in the north and northeast.