Geochemical analysis on 14 samples from seven distinct E–W trending mafic dykes from the Chotanagpur Gneissic Complex. These dykes are characterised as basalt and basaltic andesite and comparable with E-MORB type tholeiitic magma series. The dykes are classified into two groups, low Mg# and high Mg# dykes, based on their Mg# and silica content. The major fractionating mineral phases are olivine, plagioclase, and pyroxene. The dykes are variably contaminated with crustal input and also underwent post-magmatic hydrothermal alteration after their emplacement. Semi- quantitative trace element modelling suggests that these dykes are derived by partial melting within spinel peridotite-rich mantle and spinel–garnet peridotite-rich mantle source in the transition zone. The low Mg# dykes are consistent with 3–15% partial melting curves, whereas high Mg# dykes are comparable with 15% melting curve.
Citation: RAHUL PATEL, RAVI SHANKAR, D SRINIVASA SARMA and AUROVINDA PANDA, 2021. J. Earth Syst. Sci. 130:160, https://doi.org/10.1007/s12040-021-01646-7