Structure and tectonic evolution of the western continental margin of India: Evidence from subsidence studies for a 25–20 Ma plate reorganization in the Indian Ocean

Abstract

The western continental margin of India developed by Mesozoic rifting and has subsided and undergone further tectonic modification during India’s northward movement and collision with Asia. Segmentation of the margin has apparently been controlled partly by inheritance of Precambrian structures, across one of which different rates of subsidence and degrees of stretching have occurred. At about 25–20 Ma, following a widespread erosional unconformity, the rate of subsidence greatly increased both on the continental shelf and, in particular, seaward of the shelf edge (hinge line). This increased stretching occurred during reorganization of the plates in the region of the Indian Ocean, coincided with greater resistance to underthrusting of India beneath Asia, and may be related to enlargement of the Indian plate from the Owen fracture zone westward to the Dead Sea-Gulf of Aqaba shear zone.