American Geophysical Union, Tectonics, 5(34), p. 875-906, 2015
DOI: 10.1002/2014tc003780
Full text: Unavailable
Gondwana breakup since the Jurassic and the northward motion of India towards 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 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 ca. 60 Ma, and 75 and ca. 66 Ma respectively. Between ca. 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 orientated 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 ca. 20 Ma deforming the Sulaiman ranges, or at 30 Ma if the Hindu Kush slab N 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.