Strain Transformation Adjacent to the West Qinling Orogen: Implications for the Growth of the Northeastern Tibetan Plateau

Li, Zhangjun; Cheng, Feng; Hao, Ming; Young, Zachary; Song, Shangwu; Yang, Fan; Zhuang, Wenquan

doi:10.3389/feart.2021.689087

Cited by 3 publications

(2 citation statements)

References 66 publications

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“…The 3D deformation field reveals significant shear and anticlockwise rotation along the sinistral Haiyuan fault, and crustal horizontal contraction and uplift at rates of 1–3 mm/yr across the northeastern Tibet accompanied by clockwise rotation. These observations are consistent with previous studies (Hao et al., 2021; Wang & Shen, 2020), and substantiate the notion that crustal deformation induced by northeastward growth of the Tibet is primarily accommodated by block rigid rotation, crustal shortening and tectonic uplift (Cheng et al., 2021; Li et al., 2021).…”

Section: Geodetic Observations and Crustal Deformation In The Northea...mentioning

confidence: 99%

Lithospheric Rheology and Crustal Deformation Across the Northeastern Tibet and Their Implications for Plateau Growth

Li,

Cheng,

et al. 2024

Geophysical Research Letters

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Understanding lithospheric rheology is crucial in investigating tectonic evolution of intra‐continental tectonic boundary. Here, we use geodetic observations to infer lithospheric rheology across the northeastern Tibet based on a 2D viscoelastic model. Our findings reveal a lower‐crust viscosity of <1022 Pa·s underneath its margins, lower than those estimated underneath its vicinities. By comparing deformation patterns and lithospheric rheology here with those observed in the eastern Tibet, we propose that lateral variations in lower‐crust viscosity control deformation patterns and topographic gradients along the Tibet margins. The presence of low viscosity lower‐crust can lead to the development of contrasting topographic gradients and shape the plateau's geomorphology and deformation characteristics during outward growth of the Tibet. We here emphasize the subtle variations in the lower‐crust rheology between deforming blocks and the corresponding mountain ranges, which play an important role in orogeny along the intracontinental convergence boundary.

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Section: Geodetic Observations and Crustal Deformation In The Northea...mentioning

confidence: 99%

Lithospheric Rheology and Crustal Deformation Across the Northeastern Tibet and Their Implications for Plateau Growth

Li,

Cheng,

et al. 2024

Geophysical Research Letters

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“…Various studies have focused on the surface deformation and lithospheric structures in the NETP based on multi‐disciplinary methods, and different hypotheses have been put forward to interpret its geodynamic mechanisms of expansion and outward growth (Deng et al., 2018; Li & Kreemer, 2021; Y. Li et al., 2018; Z. Li, et al., 2021; Royden et al., 2008; E. Wang et al., 2012; K. Wang & Shen, 2020). For example, space‐based and ground deformation measurements can be used to ascertain the 3‐D deformation of the Earth's surface (Li et al., 2020; Liang et al., 2013; Pan et al., 2018; Wang & Shen, 2020); Geophysical materials (such as seismological and magnetotelluric observations) can be used to inverse the static structure of the lithosphere and asthenosphere (Y. Chen et al., 2018; Deng et al., 2018; C. Li et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

Moho Changes Beneath the Northeastern Tibetan Plateau Revealed by Multiple Geodetic Datasets

Zhang

Shen

et al. 2021

JGR Solid Earth

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Summary The Moho interface depths and variations provide important references to understanding the outward growth and expansion mechanisms of the Tibetan Plateau, which have drawn much attention. Here, we constrain the Moho variations beneath the northeastern Tibetan Plateau (NETP) by using multiple geodetic data and climate models. Hydrological and tectonic gravitational signals are identified from multisource data and removed from the satellite gravity observations. Moreover, the mass variation rate, resulting from vertical Moho changes is calculated. The result shows that the mass variation rate due to the Moho changes is 1.3 ± 0.6 mm/yr (equivalent water height) within the NETP, which corresponds to a Moho uplift rate of 2.7 ± 1.3 mm/yr. Additionally, we calculate the tectonic Earth surface uplift rate from GPS and leveling observations with loading and GIA (glacier isostatic adjustment) influence corrected, which gives an uplift rate of 2.2 ± 0.1 mm/yr and is similar with the Moho uplift rate. Our results indicate that the crust in the NETP is uplifted with a slight decrease in crustal thickness. Combined with the lithospheric structure from seismological tomography studies, we suggest that the crustal uplift of the NETP is mainly caused by isostatic adjustment since the delamination of the thickened lithosphere.

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The Ottawa River Gneiss Complex revisited: definition of the metamorphic core and detachment zone of a large Grenvillian metamorphic core complex

Rivers,

Schwerdtner

2024

Can. J. Earth Sci.

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Using new and published data, we synthesize the tectonic evolution of the Ottawa River Gneiss Complex (ORGC), the metamorphic core and detachment zone of a large mid- to late-Ottawan metamorphic core complex in the western Grenville Province. Field and petrologic data indicative of retrogression and exhumation, combined with maps and schematic crustal-scale sections, are used to document spatial and temporal relationships of multi-scale structures developed during its formation, of which the largest, termed mega-cross-folds and megaboudins, occur within and define the detachment zone. Mega-cross-folds, orogen-normal structures up to 70 km in length with coaxial constrictional fabrics in their hinge-lines, formed in a single phase of deformation during retrogression and exhumation. A cluster of asymmetric megaboudins, individually from 10-50 km long with granulite-facies cores and high-strain amphibolite-facies rims, similarly formed during syntectonic retrogression and exhumation of granulite-facies precursors. We argue the mega-cross-folds developed in a regime of regional transtension, whereas the megaboudin cluster formed by extensional inversion of an anastomosing early-Ottawan thrust system, with the strain patterns of both suggesting the detachment zone was the site of intense ductile flow between the stronger metamorphic core and cover. Comparison of these results with generic numerical models of extensional collapse of overthickened continental crust suggests the first-order tectonometamorphic features of the ORGC developed during necking of the upper crust and associated large-scale extensional flow of the mid and lower crust into the domiform necked region during collapse of the overthickened early-Ottawan thrust stack.

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Strain Transformation Adjacent to the West Qinling Orogen: Implications for the Growth of the Northeastern Tibetan Plateau

Cited by 3 publications

References 66 publications

Lithospheric Rheology and Crustal Deformation Across the Northeastern Tibet and Their Implications for Plateau Growth

Lithospheric Rheology and Crustal Deformation Across the Northeastern Tibet and Their Implications for Plateau Growth

Moho Changes Beneath the Northeastern Tibetan Plateau Revealed by Multiple Geodetic Datasets

The Ottawa River Gneiss Complex revisited: definition of the metamorphic core and detachment zone of a large Grenvillian metamorphic core complex

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