The Tibetan Plateau is the largest mountain belt on Earth today;its rise and growth has far-fetching impacts on Asian tectonics,landscape evolution,and climate change.Although extensive geological studies have been devoted to constrain the spatioteomporal patterns of the growth of the Tibetan Plateau,the patterns remain hard to define.Previous physical models,either approximating the Asian continent as a viscous sheet or as a plastic plate,all predicted progressively northward growth of the Tibetan Plateau following the Indo-Asian continental collision since～60-50 Ma.Increasing evidence of crustal shortening and uplift in northern Tibet soon after the collision,however,challenges these models and thus our current understanding of the fundamental mechanics of continental collision.We suggest that these discrepancies may be reconciled in a geodynamic model incorporating vertically variable rheology.