Mountain Building, Tectonic Evolution, Rheology, and Crustal Flow in the Himalaya, Karakoram, and Tibet

Searle, Michael P.

doi:10.1016/b978-0-444-53802-4.00121-4

Cited by 39 publications

(56 citation statements)

References 225 publications

(333 reference statements)

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“…The Himalayan orogeny (Figure ) initiated during the final closure of Neotethys at ~50 Ma and has maintained convergence since that time [ Green et al ., ; Najman et al ., ; Searle et al ., ; Avouac , ; Searle , ]. In the Annapurna‐Dhaulagiri Himalaya (Figure ), the GHS is bound below and above by the Main Central Thrust (MCT; top‐SW) and South Tibetan Detachment (STD; top‐down‐ENE) and may be subdivided into the Main Central Thrust Zone (MCTZ), Upper Greater Himalayan Sequence (UGHS), and South Tibetan Detachment System (STDS) [ Larson and Godin , ; Carosi et al ., ; Parsons et al ., , , ].…”

Section: The Annapurna‐dhaulagiri Himalayamentioning

confidence: 99%

Orogen‐parallel deformation of the Himalayan midcrust: Insights from structural and magnetic fabric analyses of the Greater Himalayan Sequence, Annapurna‐Dhaulagiri Himalaya, central Nepal

et al. 2016

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The metamorphic core of the Himalaya (Greater Himalayan Sequence, GHS), in the Annapurna‐Dhaulagiri region, central Nepal, recorded orogen‐parallel stretching during midcrustal evolution. Anisotropy of magnetic susceptibility and field‐based structural analyses suggest that midcrustal deformation of the amphibolite facies core of the GHS occurred under an oblate/suboblate strain regime with associated formation of low‐angle northward dipping foliation. Magnetic and mineral stretching lineations lying within this foliation from the top of the GHS record right‐lateral orogen‐parallel stretching. We propose that oblate strain within a midcrustal flow accommodated oblique convergence between India and the arcuate orogenic front without the need for strain partitioning in the upper crust. Oblate flattening may have also promoted orogen‐parallel melt migration and development of melt‐depleted regions between km3 scale leucogranite culminations at ~50–100 km intervals along orogen strike. Following the cessation of flow, continued oblique convergence led to upper crustal strain partitioning between orogen‐perpendicular convergence on thrust faults and orogen‐parallel extension on normal and strike‐slip faults. In the Annapurna‐Dhaulagiri Himalaya, orogen‐parallel stretching lineations are interpreted as a record of transition from midcrustal orogen‐perpendicular extrusion to upper crustal orogen‐parallel stretching. Our findings suggest that midcrustal flow and upper crustal extension could not be maintained simultaneously and support other studies from across the Himalaya, which propose an orogen‐wide transition from midcrustal orogen‐perpendicular extrusion to upper crustal orogen‐parallel extension during the mid‐Miocene. The 3‐D nature of oblate strain and orogen‐parallel stretching cannot be replicated by 2‐D numerical simulations of the Himalayan orogen.

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Section: The Annapurna‐dhaulagiri Himalayamentioning

confidence: 99%

Orogen‐parallel deformation of the Himalayan midcrust: Insights from structural and magnetic fabric analyses of the Greater Himalayan Sequence, Annapurna‐Dhaulagiri Himalaya, central Nepal

et al. 2016

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“…For instance, the Karakoram metamorphic sequence has undergone great amounts of crustal thickening (70-90 km), leading to partial melting, and its exhumation would have been led by transpression followed by debated amounts of strike-slip motion (eg. Searle, 2015). The spatial association between high-grade metamorphic rocks and crustal-scale shear zones is still debated, although it is noted along many orogenic belts spanning from the Proterozoic to present day (eg.…”

Section: Comparison With Syn-compressional Exhumation In Other Orogenmentioning

confidence: 99%

“…However distinct exhumation patterns are reported in different domains throughout both orogenies, reflecting a variety of tectonic processes (eg. Gapais et al, 2009 ;Lardeaux et al, 2014 ;Searle, 2015). Throughout the India-Asia collision zone, accommodation of present day shortening remains debated from the upper crust down into the upper mantle (eg.…”

Section: Comparison With Syn-compressional Exhumation In Other Orogenmentioning

confidence: 99%

“…Throughout the India-Asia collision zone, accommodation of present day shortening remains debated from the upper crust down into the upper mantle (eg. Replumaz et al, 2014;Searle, 2015). Seismic ~100 km relative to the upper and lower crust, at c. 23-15 Ma, and driven from topography overburden, underthrusting and up to 20-25 km of erosion since the Miocene (eg.…”

Section: Comparison With Syn-compressional Exhumation In Other Orogenmentioning

confidence: 99%

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Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

et al. 2018

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The Maures-Tanneron Massif (MTM), together with Corsica and Sardinia, represent the Southeastern branch of the huge European Variscan belt. A continuous evolution from continental collision to exhumation is described from ca. 350 Ma to ca. 320 Ma, based on an extended compilation of available geological and geochronogical data. This geological compilation is complemented with thermo-mechanical modelling that tests the conditions under which deep-seated HP units can melt and exhume massively during continued convergence. We simulate in two-dimensions the development of gravitational instabilities in a partially melting crust, depending on rheological layering and heat sources, and accounting for temperature dependent elasto-visco-plastic rheologies. In order to reproduce PT exhumation patterns in the MTM, over the appropriate time-scale (>20 My) and spatial extent (>100 km), a best fit was obtained with a convergence rate of 0.5 cm/yr and moderate diffusive surface processes. The contribution of radiogenic heating in the pre-stacked felsic crustal units is crucial. A lateral alternation with mafic units is also required in order to prevent lateral spreading of the orogen. A low viscosity partially molten crust (10² Pa.s, thus rather felsic) accompanies crustal exhumation in a decoupled mode from the deeper mantle. A shallow asthenosphere below the orogen (LAB at ~70 km depth, eg. shallow slab break-off) produces too warm and sudden exhumation as opposed to a competent mantle lithosphere (120 km depth LAB) that restrains it. The MTM witnesses the typical competition between far-field plate convergence and internal body forces, and our study pleads for a progressive evolution of transpression towards perpendicular extension from ca. 320 Ma.

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“…The timing of continental collision between India and Asia is important for many reasons and thus has been the subject of intense studies. The magmatic, sedimentary and metamorphic rocks of the Himalayan and Gangdese Mountains record details of important tectonic processes operating during the closure of the Neo-Tethys Ocean and the subsequent India-Asia continental collision (e.g., [1][2][3][4][5]). In particular, northward subduction of the Neo-Tethys oceanic slab beneath the southern margin of the Asian continent is evident from the occurrence of not only obducted ophiolite complexes on the northern margin of the India continent but also magmatic arc systems (e.g., the Kohistan, Ladakh and Gangdese arcs) close to the southern margin of the Asian continent.…”

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confidence: 99%

The timing of continental collision between India and Asia

Zheng

2018

Science Bulletin

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Mountain Building, Tectonic Evolution, Rheology, and Crustal Flow in the Himalaya, Karakoram, and Tibet

Cited by 39 publications

References 225 publications

Orogen‐parallel deformation of the Himalayan midcrust: Insights from structural and magnetic fabric analyses of the Greater Himalayan Sequence, Annapurna‐Dhaulagiri Himalaya, central Nepal

Orogen‐parallel deformation of the Himalayan midcrust: Insights from structural and magnetic fabric analyses of the Greater Himalayan Sequence, Annapurna‐Dhaulagiri Himalaya, central Nepal

Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

The timing of continental collision between India and Asia

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