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.

Preexisting lateral variations in crustal thickness and lithospheric thermal state are documented for the formation of some orogenic plateaux. Here we use high‐resolution 3‐D thermo‐mechanical simulations to investigate the influence of preexisting lateral lithospheric strength heterogeneity on the growth of orogenic plateau. The modeling results illustrate an episodic scenario for plateau growth: (1) an early rapid growth stage, characterized by rapid surface uplift and intensive crustal buckling and thickening; (2) an outward spreading stage, characterized by significant lateral expansion of the plateau edges; and (3) a mature stage, characterized by the development of the intracrustal partial melting and subduction of the surrounding lithosphere under the plateau. Sensitivity analyses indicate that lateral variation in crustal thickness favors outward spreading of orogenic plateau, while lateral variation in geothermal gradient favors crustal buckling. The model in absence of lateral strength heterogeneity leads to progressive migration of orogenic belt. Our models show that the plateau's lower crust is largely coupled with underlying lithospheric mantle and does not flow into the surrounding lithospheres, casting doubt on the lower crust flow model. We suggest that the Himalayan‐Tibetan orogenic system can be best understood within the framework that the proto‐southern Asian margin was fairly weak prior to the India‐Asia collision to steer the formation of a large hot orogenic plateau there.

As the largest basin on Mars, Utopia Planitia has both experienced and recorded variations of the Martian palaeoclimate. Layered subsurface structures have been identified by ground-penetrating radar in southern Utopia Planitia but lateral variations of the subsurface, potentially linked to the Martian palaeoclimatic evolution, have not been investigated. Here we report the lateral frequency-variation patterns of Zhurong radar reflections and interpret them as buried polygonal terrain below a depth of 35 m. Sixteen polygonal wedges were identified within ∼1.2 km distance, suggesting a wide distribution of such terrain under Utopia Planitia. The contrast above and below ∼35 m depth represents a notable transformation of aqueous activity or thermal conditions in the Late Hesperian–Early Amazonian. The interpreted buried polygons, possibly generated by freeze–thaw cycles, imply that there was a strong palaeoclimatic variability at low-to-mid latitudes (∼25° N), potentially due to the high obliquity of ancient Mars.