Lizardite–chrysotile veins from Vempalle Formation of Cuddapah Supergroup, India: a study in fluid–rock interaction

Much work has been done on hydrothermal alteration and serpentinization of high-magnesian bulks like dunite or peridotite. In contrast, serpentinization of dolomite has received scant attention. In this study we focus on a system of nearly monomineralic intersecting veins comprising serpentine or epidote or calcite developed within Vempalle dolomite of unmetamorphosed Cuddapah Supergroup of rocks, Eastern Dharwar Craton, India. Our studies show that hydrothermal alteration under moderately low temperature, low pressure and moderate silica activity can lead to extensive serpentinization of the dolomitic host. Deve­lopment of talc can occur under increased silica activity at similar P–T conditions. We also explore the mecha­nism of formation of chrysotile veins, epidote veins and calcite veins that transect the lizardite which replaces dolomite