Geochemical characteristics of kimberlite rock of the Anantapur and Mahbubnagar districts, Andhra Pradesh, South India

A comparative study of kimberlite rocks exposed in the Anantapur and Mahbub nagar districts and the reinterpretation of published data revealed conside rable differences between kimberlites of Anantapur and Mahbubnagar. The kim berlites of Mahbubnagar show high concentrations of Ni, Cr, Co, Zr, Hf, Ta, Th and U and lower abundance of Rb, Sr and Ba relative to Anantapur. The r elationships of Ni-Cr, Zr-Hf, Nb-Ta and Th-U show that the Mahbubnagar kimb erlites are distinctly different from the Anantapur kimberlites. The minera logical and chemical characteristics of the Mahbubnagar kimberlites differ from that of typical kimberlite and lamproite. The Ce/Y vs Zr/Nb and Zr/Nb vs La/Yb plots suggest that the Mahbubnagar kimberlites formed by higher de grees of partial melting of the mantle source than that of Anantapur kimber lites. (C) 2001 Elsevier Science Ltd. All rights reserved.