Geochemistry of the siliciclastic sediments in the Barak basin, Indo-Burma Range, India: Insights into provenance, paleoclimate, and depositional history

Abstract

Sedimentation of the Paleogene and Neogene belts in the Indo-Burma Range (IBR) involved a complex tectonic system letting provenance of both the belts poorly constrained. We made an attempt to investigate provenance, tectonic setting, paleoclimate, and depositional environment of the Renji Formation (Paleogene belt) and the Bhuban Formation (Neogene belt) in the Barak basin of western Manipur employing whole-rock geochemistry and petrography. A semi-arid climatic condition has been indicated for the weathering and liberation of sediments in the source terrain. Derivation of first cycle sediments from mafic and felsic rocks with minor contribution from the metamorphic rocks is suggested but the former seems to have dominated the Renji Formation. A shift in the provenance vis-a-vis differential chemical weathering of the mafic-felsic rocks at the source is attributed. Research results also suggest supply from deformed and elevated craton, presumably the Indian craton, during the Himalayan orogeny. Sedimentation of the Renji Formation took place in a sub-oxic deltaic environment in contrast to the Bhuban Formation which developed in an oxic shallow marine mixed tidal flat environment.