DISTRIBUTION OF MAJOR ELEMENTS IN SEDIMENTS OF THE BARA FORMATION, SOUTHERN INDUS BASIN, PAKISTAN

The Bara Formation sandstone samples from Ranikot, Lakhra and Thar coalfield areas were analyzed for observing the distribution of major elements, in order to trace the provenance and tectonic setting of the Bara Formation, from the Lower Indus Basin. The geochemical classification of Bara Formation sandstone shows the nature of sandstone as the iron sandstone, litharenite, sublitharenite and arkoses. Majority of Bara Formation sediments of Ranikot and Lakhra localities indicate active continental margin tectonic setting, along with oceanic island arc tectonic setting; whereas its samples from Thar coal field area indicate an oceanic island arc tectonic setting. The studied sediments indicate the mafic igneous and recycled sedimentary provenance with minor amount of felsic and intermediate igneous rock provenance. The CIA and PIA values indicate that the Thar sediments had suffered very intensive weathering, whereas the sediments of western part (Ranikot and Lakhra) deposited under low weathering conditions.