Petrography, diagenesis and depositional environment of the Late Proterozoic cave-temple arenites of Badami Group, Karnataka

Abstract

The Late Proterozoic Cave-Temple Arenite member of Badami Group comprising predominantly of sandstone forms one of the most interesting litho-units exposed around Badami for its prominent topographic expression (flat topped barren hillocks) along with a host of sedimentary structures viz. Cross-bedding, ripple marks, groove casts, convolute lamination etc. These sandstones are medium to coarse grained, moderate well sorted, subrounded to well rounded and belong to the quartz arenite to sub-arkose categories. Compositionally these rocks show considerabie maturity with abundant quartz (78-96 percent) and subordinate feldspars having undergone both the physical (compaction and pressure solution) and chemical (silica, calcite and hematite cementation) diagenetic changes. Mineralogical composition of these sandstones indicates a principal recycled orogen source. The variety of sedimentary structures and the textural characters suggest a shallow marine depositional environment of the sandstones.