Geochemistry of Dykes around Arabail, Western Dharwar Craton and Petrogenetic Inferences

High Mg-tholentic dykes occur around Arabail in the Dharwar-Shimoga schist belt in Western Dharwar Craton. They are olivine-rich to quartz poor-normative type. The dykes are enriched in light rare earth elements (Σ 47-63, La_N/Yb_N,=78 to 1327). Their composition is analogous to Continental Flood Basalts. The geochemical characteristics suggest that source magmas are partial melts of periodotitic mantle followed by fractional crystallization. The composition of the dykes appears to have been controlled by olivine and pyroxene fractionation followed by plagioclase in the late phase of fractionation. The dyke magma may have been formed by decompression melting consequence of lithospheric extension, crustal thinning or plume impingement at the base of the lithosphere. Deep extensional fracture systems might have served as conduits for emplacement of the dykes.