Origin of the Rajmahal Traps and the 85°E Ridge: Preliminary reconstructions of the trace of the Crozet hotspot

The 85°E Ridge is a buried aseismic ridge approximately parallel to and west of the Ninetyeast Ridge in the northeastern Indian Ocean. It was previously shown to be of probable volcanic origin emplaced on very young oceanic crust, but no satisfactory model of emplacement of the rocks was offered. We propose a model of origin of the Rajmahal Traps of northeastern India, the 85°E Ridge, and Afanasy Nikitin Seamount as the trace of the hotspot that now lies beneath the Crozet Islands in the southern Indian Ocean. This reconstruction places the Kerguelen hotspot, which formed the Ninetyeast Ridge, at the triple junction between Greater India, Australia, and Antarctica before the breakup of eastern Gondwana.