Kimberlites of Raichur and Wajrakarur Kimberlite fields from Eastern Dharwar Craton (Southern India): A comprehensive geochemical study

The paper deals with the geochemistry of kimberlites of Raichur and Wajrakarur area from the western side of Cuddapah basin and their comparison with the kimberlites of India and West and South Africa. The Archaean Dharwar craton in peninsular India is typically composed of granitegreenstone terrain with a tonalite-trondhjemite-granodiorite (TTG) and peninsular gneissic basement with intrusions of Raichur (RKF) and Wajrakarur (WKF) kimberlites. Petrographic studies reveal that the RKF kimberlites belong to tuffisitic and coherent facies which are significantly altered, whereas the WKF kimberlites have hypabyssal facies character and unaltered. Geochemically, the SiO2 content in the RKF kimberlites is both lowest and highest. The Wajrakarur kimberlites have elevated MgO concentration, whereas high CaO content is noticed in the Siddanpalli kimberlites. Fe2O3 and TiO2 concentrations are high in the Kalayandurg kimberlites. The P2O5 composition of the Siddanpalli kimberlites is high. The MgO, CaO, and TiO2 composition of Siddanpalli kimberlites are similar to that of kimberlites from West Africa, and due to contamination of carbonate sediment, the Siddanpalli kimberlites have high concentration of CaO content. The Kimberlites under study also exhibit high concentration of LILE, LREE and depletion in HFSE, HREE contents. Negative depletions of Nb and Ti are typically considered to be subduction-related signatures.