Do along-strike tectonic variations in the Nepal Himalaya reflect different stages in the accretion cycle? Insights from numerical modeling - Archive ouverte HAL Access content directly
Journal Articles Earth and Planetary Science Letters Year : 2017

Do along-strike tectonic variations in the Nepal Himalaya reflect different stages in the accretion cycle? Insights from numerical modeling

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Abstract

Whereas the large-scale morphology and dynamics of orogenic wedges are well explained by critical-taper theory, many questions remain unanswered regarding the details of how deformation is accommodated internally. Here, we investigate the dynamics of a collisional orogenic wedge bounded by an over-thickened continental plateau, using two-dimensional thermo-mechanical numerical models. These models, applied to the Himalayan orogen and compared with reference cross-sections, lead us to propose a new hypothesis to explain along-strike variations in tectonic style, topography and exhumation patterns observed along the Himalayan range by a combination of two mechanisms. First, numerical models produce a cycle of crustal ramp formation and advection toward the rear of the wedge. The asynchronous evolution of this cycle along different segments of the range may account for the well-documented lateral variations in the geometry of the Main Himalayan Thrust (MHT) and for the existence of a well-defined topographic transition in some segments of the range. Second, the models suggest that the formation of duplexes leading to the isolation of klippen along the range front may be controlled by rheological contrasts between the Tibetan plateau and/or the Greater Himalayan Sequence and the colliding Indian plate.
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insu-03596059 , version 1 (03-03-2022)

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Jonathan Mercier, Jean Braun, Peter van Der Beek. Do along-strike tectonic variations in the Nepal Himalaya reflect different stages in the accretion cycle? Insights from numerical modeling. Earth and Planetary Science Letters, 2017, 472, pp.299-308. ⟨10.1016/j.epsl.2017.04.041⟩. ⟨insu-03596059⟩
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