Kimberlite from Rajmahal magmatic province: Sr-Nd-Pb isotopic evidence for Kerguelen plume derived magmas

Abstract

Previous studies showed that the Rajmahal-Sylhet-Bengal (RSB) flood basalt province (117 ± 2 Ma) in eastern India was spatially close to the active Kerguelen hotspot about 118 Ma ago. Yet, it could not be unequivocally correlated to this hotspot due to wide variation in isotopic compositions of both the RSB and Kerguelen plateau basalts. However, we report Sr-Nd-Pb isotopic compositions (⁸⁷Sr/⁸⁶Sr_i: 0.70535 to 0.70561; ε_Nd(T): -2.6 to -3.2; ²⁰⁶Pb/²⁰⁴Pb_i: 17.88 to 18.07) of a co-eval (116 ± 2 Ma) Group II kimberlite from this flood basalt province that is identical to recently identified pristine Kerguelen plume basalts from the Kerguelen Plateau/Archipelago and Broken Ridge. This suggests that the Kerguelen hotspot could indeed be responsible for the ˜117 Ma magmatic activity in Eastern India.