TECTONIC SETTING, PETROCHEMISTRY AND TUNGSTEN METALLOGENY OF THE SEWARIYA GRANITE IN THE SOUTH DELHI FOLD BELT, RAJASTHAN

The Sewariya granite, 'largest of the Erinpura granite intrusions' occ urs along the western margin of the Middle-late Proterozoic South Delh i Fold Belt. Synkinematic with the Delhi orogeny, the granite body int rudes a rifted back are type basin (Barotiva Formation) and hosts W +/ - Sn +/- Li mineralization in pneumatolytic quartz veins. Innumerable metasedimentary enclaves occur which are traversed by syn-to post-tect onic ductile shear zones. Geochemistry of the granite suggests it to b e a well differntiated, calc-alkaline, S-type metallogenetically speci alised orogenic massif. The nature of the granite and the host supracr ustals and the tectonic discriminant diagrams indicate that it may hav e 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 conspi cuous 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 associate d with felsic plutonic suites of contrasting geotectonic environments, W-Sn mineralization along this belt defines a single metallogenic pro vince, a large part of which is unexplored.