Origin of Ca in South Indian calcretes developed on metamorphic rocks

Calcrete profiles developed on Precambrian silicate rocks in south peninsular India are studied and compared in terms of mineralogical, chemical and isotopic composition. The aim of this study is to determine the origin of calcium and the processes governing the development of a minor economic deposit in different geomorphic settings. The investigation integrates observations from an outcrop to a microfabric scale and reveals that the origin of calcium is local and linked with the weathering of the minerals of the surrounding rocks. The CaCO3 precipitation occurs after vertical and lateral translocation in the slope system.