The Himalayan Arc: large-scale continental subduction, oroclinal bending and back-arc spreading

Palaeomagnetic results from the Himalayan Arc and Southern Tibet compared with simulated apparent polar wander paths for the Indian plate show a consistent pattern of rotations of the Himalayan Arc relative to the Indian Shield, varying gradually from 45° clockwise in the northwestern Himalaya to slightly counterclockwise in the Lhasa region. This pattern is consistent with continental underthrusting of Greater India beneath the Tibetan Plateau since the Early Miocene over at least 650 km at the longitude of western Nepal and oroclinal bending since the latest Miocene. Available palaeomagnetic observations support the steady-state model for the formation of the Himalayan Arc, with refinements as follows: (1) collision between Greater India's northern boundary and southern Asia occurred at equatorial latitudes, with progressive suturing from Palaeocene in the northwestern Himalaya until Early Eocene in the eastern Himalaya; (2) continuing convergence and indentation of Greater India into southern Asia over about 2000 km up to the Early Miocene resulted in southeastward extrusion of Indochina; and (3) Neogene counterclockwise rotational underthrusting of Greater India along the Main Central Thrust, with Pliocene/Quaternary oroclinal bending of the Himalayan Arc.