Petrochemistry of ultramafic rocks of Anara-Asanboni areas in North Puruliya Shear Zone (NPSZ), West Bengal, India

Number of outcrops of ultramafic rocks occur aligned parallel to North Puruliya Shear Zone (NPSZ) near Anara-Asaboni areas and are intruded within high grade Proterozoic rocks of Chotanagpur Gneissic Terrain (CGT). These rocks occur as small lenses, pockets, veins, thin dykes and are spatially associated with mafic rocks. These ultramafic rocks are composed of clinopyroxene, orthopyroxene, olivine, plagioclase, hornblende, phlogopite and opaques and exhibit evidence of extensive shearing. The geochemical signature of the rocks show a significant variation in major, trace and REE concentration. Linear correlation of chemical attributes suggests fractionation controlled magmatic differentiation. Geochemical characteristics suggest their derivation either from enriched mantle source and/or by crustal contamination during emplacement.