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Structures and properties of Tibetan lithosphere control the India‐Asian collision and plateau evolution: Numerical modeling
Author(s) -
Li ZhongHai,
Huangfu Pengpeng
Publication year - 2019
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13948
Subject(s) - geodynamics , beijing , chinese academy of sciences , lithosphere , china , collision zone , key (lock) , geography , library science , geology , earth science , computer science , tectonics , paleontology , archaeology , computer security
Lithosphere delamination is believed to have played a major role in mountain building and also in the Tibetan plateau evolution; however, the styles and dynamics of delamination remain poorly understood. Using high-resolution thermo-mechanical models, we systematically investigated the conditions for the initiation of lithosphere delamination during orogenesis of continental collision and explored the key factors that control the various modes of delamination. Our results indicate that the negative buoyancy from lithosphere thickening during orogenesis could cause delamination, when the reference density of the lithospheric mantle is not lower than that of the asthenosphere. In these cases, compositional rejuvenation of depleted continental lithosphere by magmatic/metasomatic plumeand/or subduction-induced processes may play crucial roles for subsequent lithosphere delamination. If the reference density of the lithospheric mantle is less than that of the asthenosphere, additional promoting factors such as lower crustal eclogitization are required for delamination to occur. Based on systematic numerical simulations, three basic modes of lithosphere delamination are predicted: pro-plate delamination, retro-plate delamination, and a transitional double-plates (both proand retro-plate) delamination. Pro-plate delamination is favored by low convergence rates, high lithospheric density and a relatively strong retro-plate, whereas retro-plate delamination requires a weak retro-plate. The Central-Northern Tibetan plateau is a possible geological analogue for the retro-plate delamination modes. Our model also shows significant impact of delamination on the topographic evolution of orogens. Large-scale lithosphere delamination in continental collision zones would lead to wide and flat plateaus, whereas relatively narrow and steep mountain belts are predicted in orogens without major delamination.