Tectonic interactions between India and Arabia since the Jurassic reconstructed from marine geophysics, ophiolite geology, and seismic tomography

Abstract

Gondwana breakup since the Jurassic and the northward motion of India toward Eurasia were associated with formation of ocean basins and ophiolite obduction between and onto the Indian and Arabian margins. Here we reconcile marine geophysical data from preserved oceanic basins with the age and location of ophiolites in NW India and SE Arabia and seismic tomography of the mantle below the NW Indian Ocean. The North Somali and proto-Owen basins formed due to 160-133-Ma N-S extension between India and Somalia. Subsequent convergence destroyed part of this crust, simultaneous with the uplift of the Masirah ophiolites. Most of the preserved crust in the Owen Basin may have formed between 84 and 74-Ma, whereas the Mascarene and the Amirante basins accommodated motion between India and Madagascar/East Africa between 85 and circa 60-Ma and 75 and circa 66-Ma, respectively. Between circa 84 and 45-Ma, oblique Arabia-India convergence culminated in ophiolite obduction onto SE Arabia and NW India and formed the Carlsberg slab in the lower mantle below the NW Indian Ocean. The NNE-SSW oriented slab may explain the anomalous bathymetry in the NW Indian Ocean and may be considered a paleolongitudinal constraint for absolute plate motion. NW India-Asia collision occurred at circa 20-Ma deforming the Sulaiman ranges or at 30-Ma if the Hindu Kush slab north of the Afghan block reflects intra-Asian subduction. Our study highlights that the NW India ophiolites have no relationship with India-Asia motion or collision but result from relative India-Africa/Arabia motions instead. Key Points We present a new tectonic model for the evolution of NW Indian Ocean Subducted slab under the Carlsberg Ridge resulted from Arabia-India convergence