GEOCHEMISTRY OF THE PHYLLITES OF THE COPPER MOUNTAIN REGION, SANDUR SCHIST BELT, KARNATAKA

Chemical composition of the phyllites of the Copper Mountain region of the late Archaean Sandur Schist belt in the eastern block of the Dhar war craton indicates that the fine-grained elastic sediments from whic h they were formed, were derived from a provenance comprising similar to 60% felsic, similar to 30% mafic and similar to 10% ultramafic rock s. High Zr/Nb and Zr/Y ratios; and lack of strong -ve Eu anomalies sug gest that the felsic component of the provenance was dominantly made u p of tonalites-trondhjemites; granites and granodiorites were very sub ordinate constituents. The sediments appear to have accumulated in a c ontinental island are environment. Rarity of granitic constituents in the pre-Dharwar provenance of Sandur basin contrasts with the abundanc e of such constituents in the provenance for the fine-grained elastic sediments of basins in the western block of the Dharwar craton. The co ntinental crust of the eastern block was apparently less evolved durin g the pre-Dharwar time as compared to that in the western block of the Dharwar craton.