Mineral–fluid interactions in the late Archean Closepet granite batholith, Dharwar Craton, southern India
Résumé
The chemical composition of different rocks as well as volatile-bearing and volatile-free mineralshas been used to assess the presence of fluids in the Closepet batholith and to estimate the intensity ofthe fluid−rock interactions. The data were processed using polytopic vector analysis (PVA). Additional datainclude measurements of water content in the structure of volatile-free minerals and an examination of growthtextures. The composition of mineral domains indicated formation/transformation processes with commonfluid−mineral interactions. In general, the results suggested that the processes occurred in a ternary system.Two end-members were likely magmas and the third was enriched in fluids. In contrast, analysis of the apatitedomains indicated that they likely formed/transformed in a more complex, four-component system. This systemwas fluid-rich and included hybrid magma with a large mafic component. PVA implies that the fluids do notappear to come from one source, given their close affinity and partial association with mantle-derived fluids. Adynamic tectonic setting promoting heat influx and redistribution, and interaction of fluids suggests that the formation/transformation processes of minerals and rocks occurred in a hot-spot like environment.
