Transition from alluvial to wave-tide-dominated Meso-Neoarchean shelf sedimentation in the Mankarchua Quartzite, Singhbhum craton, eastern India

Abstract

The Mankarchua Quartzite is a 300 m thick arenite-dominated succession developed on the southwestern margin of the Singhbhum craton, eastern India. Detrital zircon dates available from the succession suggest the age of the youngest population at 2.9 Ga. The arenite dominant succession with very low degree of deformation or metamorphic overprint preserves the depositional primary sedimentary structures and petrography for reconstruction of depositional setting and tectonic setting with considerable clarity. We classified the Mankarchua Quartzite into three members, namely, in the ascending order, the Rajabasa Member, the Timi Member and the Gurusanga Member. Facies analysis on the succession identifies eleven sedimentary facies that can be related to basin margin alluvial fan, wave-/tide-dominated lower shoreface to shelf transitional environments. The entire succession represents a lower order transgressive sequence presumably controlled by tectono-eustatic base level rise and drowning of a continental shelf. Three members can be related to higher order cycles that are likely to have resulted from local scale basin margin tectonics. Paleocurrent patterns corroborate to the alluvial fan/braided stream and wave-/tide-dominated depositional settings. The succession records transition in a narrow interval from coarse-grained conglomerate-pebbly sandstone to sandstone-siltstone-mudstone dominated facies associations in a Meso-Neoarchean drowning shelf.