State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia.
Nat Commun. 2017 Jul 19;8:15992. doi: 10.1038/ncomms15992.
The formation of the Tibetan plateau during the India-Asia collision remains an outstanding issue. Proposed models mostly focus on the different styles of Tibetan crustal deformation, yet these do not readily explain the observed variation of deformation and deep structures along the collisional zone. Here we use three-dimensional numerical models to evaluate the effects of crustal rheology on the formation of the Himalayan-Tibetan orogenic system. During convergence, a weaker Asian crust allows strain far north within the upper plate, where a wide continental plateau forms behind the orogeny. In contrast, a stronger Asian crust suppresses the plateau formation, while the orogeny accommodates most of the shortening. The stronger Asian lithosphere is also forced beneath the Indian lithosphere, forming a reversed-polarity underthrusting. Our results demonstrate that the observed variations in lithosphere deformation and structures along the India-Asia collision zone are primarily controlled by the strength heterogeneity of the Asian continental crust.
青藏高原在印度-亚洲碰撞过程中的形成仍然是一个悬而未决的问题。提出的模型主要集中在藏区地壳变形的不同风格上，但这些模型不容易解释沿碰撞带观察到的变形和深部结构的变化。在这里，我们使用三维数值模型来评估地壳流变学对喜马拉雅-青藏高原造山系统形成的影响。在汇聚过程中，亚洲地壳较弱使得应变可以延伸到上板块的更北位置，在造山带之后形成一个宽阔的大陆高原。相比之下，一个较强的亚洲地壳抑制了高原的形成，而造山带则容纳了大部分缩短。较强的亚洲岩石圈也被印度岩石圈强迫向下俯冲，形成反向极性俯冲。我们的结果表明，沿印度-亚洲碰撞带观察到的岩石圈变形和结构的变化主要受亚洲大陆地壳强度非均一性的控制。
