Tectonic Setting, Petrochemistry and Tungsten Metallogeny of the Sewariya Granite in the South Delhi Fold Belt, Rajasthan

The Scwariya granite, 'largest of the Erinpura granite intrusions' occurs along the western margin of the Middle-Late Proterozoic Soulh Delhi Fold Bell. Synkincmalic with the Delhi orogeny, the granite body intrudes a rifled back arc type basin (Barotiya Formation) and hosts W ± Sn ± Li mincralization in pneumatolytic quartz veins. Innumcrable metasedimentary enclaves occur which are traversed by syn-to post-tectonic ductile shear zones. Geochemistry of Ihe granite suggests it to be a well differntiated, calc-alkliline, S-typc metallogcnetically specialised orogenic massif. The nature of the granite and the host supracrustals and Ihe tectonic discriminant diagrams indicate that it may have evoled in an arc-related environment. W ± Sn ± Li mineralization in this granite, Pb-Zn-Cu and Zn-Cu mineralization in the contiguous units of Barotiya and Sendra formations respectively suggests a conspicuous metallogenic zoning.

The Sewariya granite forms a central link to the major Sn-W hosted granite rocks in Rajasthan Haryana sector that lie along a 500 km long NNE-SSW trending lineament. Although associated with felsic plutonic suites of contrasting geotectonic environments, W -Sn mineralizalion along this belt defines a single metallogenic province, a large part of which is unexplored.