Paleoproterozoic dolomite-hosted talc mineralization in Cuddapah basin, India: A dynamic model.

Field and petrographic evidences from the Vempalle Formation of the Cuddapah basin suggest that talc can form by replacing host rock dolomite. Here, we present a mass balance calculation, based on volume, for the replacement of host rock dolomite by talc. The volume-conservative replacement process is thought to be driven by the crystallisation stress that develops during the growth of talc within the rigid host. The crystallization stress induced during talc-for-dolomite replacement can exceed the direct tensile strength and uniaxial compressive strength of dolomite, potentially creating micro-fractures that cross-cut primary stratification, promote fluid migration and subsequent talc mineralization. The fluid influx required to complete talc mineralization in dolomite hosts is substantial (approximately 1.32 × l06 L for the complete replacement of 1 m3 of dolomite) and is consistent with the findings from other independent studies. Model results suggest that talcification of dolomite depends on temperature, reactive surface area, saturation of fluid with respect to talc, and host rock porosity. [ABSTRACT FROM AUTHOR]