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.

Estimation of Depth to Bottom of Magnetic Sources Using Spectral Methods: Application on Iran's Aeromagnetic Data

“…The most striking feature of the map is the deep DBMS (~40 km thick) over Makran accretionary wedge. The deep DBMS is in agreement with the presence of a thick sedimentary cover of >10 km (Teknik & Ghods, ) overlying over an old (~80–100 Ma, Gaina et al, ) almost flat oceanic lithosphere (e.g., Penney et al, ). The oceanic plate cooling model of Stein and Stein () suggests a depth of ~40 km for Curie isotherm of the oceanic lithosphere of age 80–100 Ma, closely in agreement with the calculated DBMS in the Makran accretionary wedge.…”

Intraplate Deformation of Oceanic Crust in the West Somali Basin: Insights From Long‐offset Reflection Seismic Data

“…The location of the spreading axis first derived from seismic, gravity, and magnetic data in the 80s (Cochran, ) has been confirmed by satellite‐derived, free‐air gravity data (Davis et al, ; Phethean et al, ; Sauter et al, ). Spreading was directed N‐S before the extinction, but a NNW‐SSE direction is inferred from gravity lineaments in the older oceanic crust fabric close to the Somalian margin (Figure ) (Davis et al, ; Gaina et al, ; Phethean et al, ; Seton et al, ). The age of this change of spreading direction is estimated to be 155–150 Ma in the WSB (Davis et al, ; Phethean et al, ; Reeves et al, ).…”

Tie points for Gondwana reconstructions from a structural interpretation of the Mozambique Basin, East Africa and the Riiser-Larsen Sea, Antarctica

“…Several plate kinematic models describe the breakup of Gondwana along the East African margin (e.g., Cox, 1992;Davis et al, 2016;Gaina et al, 2013Gaina et al, , 2015Eagles and König, 2008;Leinweber and Jokat, 2012;Nguyen et al, 2016;Reeves et al, 2016). It is generally accepted that the breakup of Gondwana along the East African margin took place in the Early Jurassic at about 170-180 Ma (e.g., Gaina et al, 2013Gaina et al, , 2015Leinweber and Jokat, 2012;Leinweber et al, 2013;Nguyen et al, 2016;Reeves et al, 2016).…”

“…It is generally accepted that the breakup of Gondwana along the East African margin took place in the Early Jurassic at about 170-180 Ma (e.g., Gaina et al, 2013Gaina et al, , 2015Leinweber and Jokat, 2012;Leinweber et al, 2013;Nguyen et al, 2016;Reeves et al, 2016). While earlier studies proposed that the Mozambique Basin and West Somali Basin opened in a generally N-S direction, more recent plate tectonic reconstructions argue for an almost simultaneous opening of both basins in the NW-SE direction (e.g., Gaina et al, 2013;Reeves et al, 2016).…”