A small Greater India restored by Himalayan crustal mass balance calculations

Abstract

Greater India, a postulated northern extension of the modern Indian continent that has been subducted beneath Tibetan Plateau, is needed to constrain the process of the greatest collision event between India and Asia. However, how far Greater India extends northward remains controversial, with proposed estimates from 100 to 2400 km. Here, we calculate Greater India’s size by estimating the crustal mass balance of the Himalaya, as Himalaya was created by the peeling-off of Greater India’s crust during the convergence. Our results show that Greater India only extends northward ∼ 620 km, further indicating that the Greater India continental subduction started at ∼ 24 Ma with the velocity of India from marine magnetic anomalies. This timing corresponds to the Himalayan uplift age. This result leaves open the possibility of both one-stage and two-stage India-Asia collision assuming that the massive Indian continental subduction started only long after the initial collision.