Rare Earth Element Geochemistry of Selected Mafic-Ultramafic Units from Singhbhum Craton: Implications to Source Heterogeneity

Modelling ofREE data indicates that while mafic rocks of Dhanjori Group are partial melting products of a spinel Iherzolite source, Dalma ultrabasics are the residue after the melt-extraction from an original garnet lherzolite rock. Ultramafics of Newer dolerite dykes indicate either derivation by mantle meta somatism or effect of post magmatic serpentinisation. REE data in conjunction with the available geochronological data suggest that significant mantle heterogeneity existed over relatively smaller distances (∼100 km) even during Proterozoic and that the mantle evolved in a non-uniform manner with distinct localised processes.