Facies analysis, sequence development and paleoredox condition of lower part of kaimur formation, vindhyan supergroup, central India

Abstract

The Sandstone present above the Rohtas Limestone and the overlying Bhagwar shale have been studied during the present work. Below the sandstone there is a transgressive lag which indicate a fresh start of sedimentation after the completion of deposition of Rohtas limestone. The sandstone is likely to be the equivalent of lower quartzite member and consists of two associations. Detailed sedimentological investigation suggests that it is basically a tide dominated deposit with some intervention of storms. The sandstone is followed by a shale deposits which is black in colour. Considering the detailed sedimentology and sequence stratigraphy it is likely that deposition initiated on the unconformity surface present above the Rohtas limestone followed by a transgressive system tract(TST) and the maximum flooding surface. In this transgressive sequence a glaucony horizon has been identified. The galucony minerals are rich in Mg and K2O content.