Rock-water interaction and evolution of sulphide ores in the late Archaean Chitradurga greenstone belt of southern India
H.N.B.attacharyay; A.D.M.kherjee; P.K.B.attacharyay
Mineralium Deposita 28(5): 303-309
Sulphide ore mineralization developed in proximity to iron formations in a cyclic volcano-sedimentary sequence that forms the offshore part of the late Archaean intracratonic basin of the Chitradurga greenstone belt, south India. The chemistry of volcanic suite attests to an extensive rock-water interaction resulting in exchange of Si and Na for divalent cations, including Cu, Pb and Zn. The exchange took place during hydrothermal alteration of basalt prior to its involvement in regional deformation and metamorphism. A hydrothermal convection system extracted Cu, Zn and Pb from sea-floor basalts during a static phase of evolution of the Chitradurga basin and developed the stratabound ore deposit within the pyroclastics and the stringer ores below.