Refertilization of Mantle Peridotites from the Central Indian Ridge: Response to a Geodynamic Transition

Abstract The phenomena of reactive percolation enriched asthenospheric melts and pervasive melt-rock interactions at mid oceanic ridge-rift systems are the principal proponents for mantle refertilization compositional heterogeneity. This study presents new mineralogical geochemical data abyssal peridotites exposed along Vema Vityaz fracture zones Central Indian Ridge (CIR) to address factors contributing chemical heterogeneity CIR mantle. Cr-spinel (Cr#: 0.37-0.59) chemistry classifies these rocks as alpine-type corroborates a transitional depleted MORB type enriched, SSZ-related arc-type magma composition. HFSE REE geochemistry further attests an intraoceanic forearc affinity. distinct boninitic signature reflected by LREE>MREE<HREE PGE compositions substantiates harzburgites melt concomitant initiation subduction. mineral chemistry, trace, signatures envisage (i) replenishment sub-ridge upper impregnation subduction-derived melts, (ii) tectonic transition from embryonic suprasubduction zone, (iii) spontaneous subduction submarine transform faults slow-spreading owing weakness mechanical instability older, denser, negatively buoyant Ocean lithosphere.