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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Early onset and late acceleration of rapid exhumation in the Namche Barwa syntaxis, eastern Himalaya
AU - Govin, Gwladys
AU - van der Beek, Peter
AU - Najman, Yani
AU - Millar, Ian
AU - Gemignani, Lorenzo
AU - Huyghe, Pascale
AU - Dupont-Nivet, Guillaume
AU - Bernet, Matthias
AU - Mark, Chris
AU - Wijbrans, J. R.
PY - 2020/11/1
Y1 - 2020/11/1
N2 - The Himalayan syntaxes, characterized by extreme rates of rock exhumation co-located with major trans-orogenic rivers, figure prominently inthe debate on tectonic versus erosional forcing of exhumation. Both the mechanism and timing of rapid exhumation of the Namche Barwamassif in the eastern syntaxis remain controversial. It has been argued that coupling between crustal rock advection and surface erosioninitiated in the late Miocene (8-10 Ma). Recent studies, in contrast, suggest a Quaternary onset of rapid exhumation linked to a purely tectonicmechanism. We report new multisystem detrital thermochronology data from the most proximal Neogene clastic sediments downstream ofNamche Barwa and use a thermo-kinematic model constrained by new and published data to explore its exhumation history. Modeling resultsshow that exhumation accelerated to ~4 km/m.y. at ~8 Ma and to ~9 km/m.y. after ~2 Ma. This three-stage history reconciles apparentlycontradictory evidence for early and late onset of rapid exhumation, and suggests efficient coupling between tectonics and erosion since thelate Miocene. Quaternary acceleration of exhumation is consistent with river-profile evolution, and may be linked to a Quaternary river-captureevent.
AB - The Himalayan syntaxes, characterized by extreme rates of rock exhumation co-located with major trans-orogenic rivers, figure prominently inthe debate on tectonic versus erosional forcing of exhumation. Both the mechanism and timing of rapid exhumation of the Namche Barwamassif in the eastern syntaxis remain controversial. It has been argued that coupling between crustal rock advection and surface erosioninitiated in the late Miocene (8-10 Ma). Recent studies, in contrast, suggest a Quaternary onset of rapid exhumation linked to a purely tectonicmechanism. We report new multisystem detrital thermochronology data from the most proximal Neogene clastic sediments downstream ofNamche Barwa and use a thermo-kinematic model constrained by new and published data to explore its exhumation history. Modeling resultsshow that exhumation accelerated to ~4 km/m.y. at ~8 Ma and to ~9 km/m.y. after ~2 Ma. This three-stage history reconciles apparentlycontradictory evidence for early and late onset of rapid exhumation, and suggests efficient coupling between tectonics and erosion since thelate Miocene. Quaternary acceleration of exhumation is consistent with river-profile evolution, and may be linked to a Quaternary river-captureevent.
U2 - 10.1130/G47720.1
DO - 10.1130/G47720.1
M3 - Journal article
VL - 48
SP - 1139
EP - 1143
JO - Geology
JF - Geology
SN - 0091-7613
IS - 12
ER -