Exhumation of Greater Himalayan rock along the Main Central Thrust in Nepal: implications for channel flow

Robinson, Delores M.; Pearson, Ofori N.

doi:10.1144/gsl.sp.2006.268.01.12

Cited by 31 publications

(23 citation statements)

References 64 publications

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“…Similarly, ductile shear strain and out-of-sequence thrusting that have been considered diagnostic of channel-flow models are equally compatible with conventional thrust behaviour (e.g. Robinson & Pearson 2006). However, the large-scale fold-and-thrust-belt geometry of the Himalaya, and the coherent fightside-up stratigraphic succession of the Greater and Lesser Himalayan Sequences (e.g.…”

Section: Evaluation Of Existing Channel-flow Models: Southern Tibetmentioning

confidence: 81%

Crustal flow in Tibet: geophysical evidence for the physical state of Tibetan lithosphere, and inferred patterns of active flow

Klemperer

2006

194

154

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Many seismic and magnetotelluric experiments within Tibet provide proxies for lithospheric temperature and lithology, and hence rheology. Most data have been collected between c. 88°E and 95°E in a corridor around the Lhasa-Golmud highway, but newer experiments in western Tibet, and inversions of seismic data utilizing wave-paths transiting the Tibetan Plateau, support a substantial uniformity of properties broadly parallel to the principal Cenozoic and Mesozoic sutures, and perpendicular to the modern NNE convergence direction. These data require unusually weak zones in the crust at different depths throughout Tibet at the present day. In southern Tibet these weak zones are in the upper crust of the Tethyan Himalaya, the middle crust in the southern Lhasa terrane, and the middle and lower crust in the northern Lhasa terrane. In northern Tibet, north of the Banggong-Nujiang suture, the middle and probably the lower crust of both the Qiangtang and Songpan-Ganzi terranes are unusually weak. The Indian uppermost mantle is cold and seismogenic beneath the Tethyan Himalaya and the southernmost Lhasa terrane, but is probably overlain by a northward thickening zone of Asian mantle beneath the northern Lhasa terrane. Beneath northern Tibet the upper mantle has not been replaced by subducting Indian and Asian lithospheres, and is warmer than to the south. These inferred vertical strength profiles all have minima in the crust, thereby permitting, though not actually requiring, some form of channelized flow at the present day. Using the simplest parameterization of channel-flow models, I infer that a Poiseuille-type flow (flow between stationary boundaries) parallel to India-Asia convergence is occurring throughout much of southern Tibet, and a combination of Couette (top-driven, between moving boundaries) and Poiseuille lithospheric flow, perpendicular to lithospheric shortening, is active in northern Tibet. Explicit channel-flow models that successfully replicate much of the large-scale geophysical behaviour of Tibet need refinement and additional model complexity to capture the full details of the temporal and spatial variation of the India-Asia collision.

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Section: Evaluation Of Existing Channel-flow Models: Southern Tibetmentioning

confidence: 81%

Crustal flow in Tibet: geophysical evidence for the physical state of Tibetan lithosphere, and inferred patterns of active flow

Klemperer

2006

194

154

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“…3A;Beaumont et al 2004). Although exhumation of the GHS in the Himalaya may be associated with southward extrusion along coeval STD-MCT bounding faults, it may also be locally enhanced by post-MCT warping of the GHS and localized erosion following cessation of extrusion (Thiede et al 2004;Vannay et al 2004;Godin et al 2006), and growth of duplexes in the footwall of the MCT during the middle Miocene (Robinson & Pearson 2006).…”

Section: Exhumationmentioning

confidence: 99%

Channel flow, ductile extrusion and exhumation in continental collision zones: an introduction

et al. 2006

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Abstract:The channel flow model aims to explain features common to metamorphic hinterlands of some collisional orogens, notably along the Himalaya-Tibet system. Channel flow describes a protracted flow of a weak, viscous crustal layer between relatively rigid yet deformable bounding crustal slabs. Once a critical low viscosity is attained (due to partial melting), the weak layer flows laterally due to a horizontal gradient in lithostatic pressure. In the Himalaya-Tibet system, this lithostatic pressure gradient is created by the high crustal thicknesses beneath the Tibetan Plateau and 'normal' crustal thickness in the foreland. Focused denudation can result in exhumation of the channel material within a narrow, nearly symmetric zone. If channel flow is operating at the same time as focused denudation, this can result in extrusion of the mid-crust between an upper normal-sense boundary and a lower thrust-sense boundary. The bounding shear zones of the extruding channel may have opposite shear sense; the sole shear zone is always a thrust, while the roof shear zone may display normal or ttuqast sense, depending on the relative velocity between the upper crust and the underlying extruding material. This introductory chapter addresses the historical, theoretical, geological and modelling aspects of channel flow, emphasizing its applicability to the Himalaya-Tibet orogen. Critical tests for channel flow in the Himalaya, and possible applications to other orogenic belts, are also presented.

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“…During the uplifts, the exhumation occurred. A number of data on Ar/Ar age and the monazite Th-U age suggested that in the period 11-9 Ma [65][66][67][68][69][70] the Central Himalayan Fault, the major boundary fault, and high Himalayan metamorphite system were under exhumation. Since 5Ma, the rapid uplift and exhumation events mainly occurred in the Himalayan orogenic belts.…”

Section: Neogene Low-temperature Thermochronological Recordsmentioning

confidence: 99%

Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau

Zhang

Wang

Cao

et al. 2008

Sci. China Ser. D-Earth Sci.

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Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution and tectonic evolution of the 92 Tertiary remnant basins. SouthernTibet and the Yecheng area in Xinjiang, located at southern and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene. In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly. The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê, the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at 13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different.

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Exhumation of Greater Himalayan rock along the Main Central Thrust in Nepal: implications for channel flow

Cited by 31 publications

References 64 publications

Crustal flow in Tibet: geophysical evidence for the physical state of Tibetan lithosphere, and inferred patterns of active flow

Crustal flow in Tibet: geophysical evidence for the physical state of Tibetan lithosphere, and inferred patterns of active flow

Channel flow, ductile extrusion and exhumation in continental collision zones: an introduction

Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau

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