Propagation of the deformation and growth of the Tibetan-Himalayan orogen: A review

Long-standing problems in the geological evolution of the Tibetan-Himalayan orogen include where the India-Asia convergence was accommodated and how the plateau grew. To clarify these problems, we review the deformations and their role in the plateau's growth. Our results show that ~ 1630 km of shortening occurred across the Tibetan-Himalayan orogen since ~ 55 Ma, with more than ~ 1400 km accommodated by large-scale thrust belts. These thrust belts display an outward expansion from central Tibet and couple with the surficial uplift. The development of the Tibetan plateau involved three significant steps: Primitive plateau (~ 90-55 Ma), Proto-plateau (~ 55-40 Ma), and Neoteric plateau (~ 40-0 Ma). Several processes have collaborated to produce the Proto-plateau, including the pre-existing Primitive plateau, the India-Asia collision, and subductions of Greater India and Songpan-Ganzi beneath the Lhasa-Qiangtang terrane. Since ~ 40 Ma, the Proto-plateau, which was dominated by a topographic gradient, lower crustal flow and continuous India-Asia convergence, experienced three periods of rapid outward growth (~ 40-23, ~ 23-10, and ~ 10-0 Ma) in general. The N-S trending rifts were caused by the eastward growth of the plateau dominated by thrusting and crust flow in central Tibet, while they were the results of intense N-S shortening in Himalaya.