Effects of Ninetyeast Ridge magmatism and pre India-Eurasia collision dynamics on basement and crust-lithospheric structures of the Northeastern Indian Ocean

Abstract

The coexistence of multifaceted geodynamical situation in the Northeastern Indian Ocean (Bay of Bengal) lithosphere inspires to investigate the origin, present day orientation and gravitational stability of its basement, crust and lithospheric structures. The origin, evolution and the present day configuration of these structures such as the northward down dipping of the Bay of Bengal basement and its lithosphere, the Moho of the 85°E ridge, the formation of the Ninetyeast ridge median graben and ridge normal faults and their interaction with slow convergence and stress diffusion processes in the north Andaman trench, remain conspicuous. In this paper, we explain the above mentioned processes and the existence of the Bay of Bengal basement features through plausible tectonic scenarios that related with past time dynamics of the Indian Plate prior to the India-Eurasia collision and lithospheric thermal perturbation due to the Ninetyeast Ridge magmatism.