Oblique convergence, arc-parallel extension, and the role of strike-slip faulting in the High Himalaya

Abstract

Arc-parallel extension is an important component of the active deformation of the Himalaya. This extension is accommodated via arc-perpendicular normal faults linked to arc-parallel strike-slip faults. Analysis of ~130 global positioning system geodetic velocities indicates >3 cm yr-1 of arc-parallel extension of the Himalaya. Several models have sought to explain Himalayan arc-parallel extension and strike-slip faulting, including lateral extrusion of Tibet, oroclinal bending of the Himalaya, radial spreading of Tibet and the Himalaya, and variably oblique convergence between India and the Himalaya. Predictions of each model are tested against structural and geodetic observations. These tests indicate that the oblique convergence model best describes Himalayan extensional and strike-slip deformation. © 2011 Geological Society of America.