Significant late Neogene east - west extension in northern Tibet

In one of the first papers documenting active east-west extension in Tibet, Molnar and Tapponnier (1978) attributed the extension to gravitational spreading of its thick crust. England and Houseman (1989) related extension to rapid uplift of the Tibetan plateau caused by convective removal of the lower mantle lithosphere. Other workers have argued that east-west extension in southern Tibet reflects local boundary conditions such as oblique convergence between India and Asia (McCaffery and Nabelek, 1998), outward expansion of the Himalayan arc (Seeber and Armbruster, 1984; Klootwijk et al., 1985; Molnar and Lyon-Caen, 1989; Ratschbacher et al., 1994; Seeber and Pecher, 1998), and eastward extrusion of north Tibet (Armijo et al., 1986). However, Yin and Kong (1997) proposed that the late Neogene extension in Tibet is part of widespread extension affecting much of east Asia in the past 10 m.y. (e.g., formation of the Shanxi graben and Baikal rift). The ongoing debate about the causes of late Cenozoic east-west extension in Tibet reflects, in part, a lack of information on the timing and magnitude of rifting in northern Tibet.