Geochemistry of the Archaean and Proterozoic clastic and carbonate rocks of Rajasthan, India

The late Archaean sediments in Rajasthan occur either as enclave suites within Mangalwar Complex or vast spreads of volcanics and volcaniclastic turbidites with quartzwacke of Hindoli Group. The Lower Proterozoic cover sequence of Aravalli Fold belt and Jahajpur Group were deposited in ensialic aborted rift basins dominated by shelf type elastic and carbonate sediments. Archaean clastics are essentially potassic sandstones characterised by higher LREEN/HREEN, and low Eu/Eu* ratios and greater concentrations of total REE than Proterozoic counterparts. The Archaean carbonates have low REE (total), higher Co, Cr and higher Eu/ Eu*, Eu-N/Sm-N, La/Th and La/Sc ratios, compared to the Proterozoic Carbonates. A passive margin setting basin support the rift related clastic and carbonate deposition.