A review of the geologic history of the Himalayan-Tibetan orogen suggests that at least 1400 km of north-south shortening has been absorbed by the orogen since the onset of the Indo-Asian collision at about 70 Ma. Significant crustal shortening, which leads to eventual construction of the Cenozoic Tibetan plateau, began more or less synchronously in the Eocene (50–40 Ma) in the Tethyan Himalaya in the south, and in the Kunlun Shan and the Qilian Shan some 1000–1400 km in the north. The Paleozoic and Mesozoic tectonic histories in the Himalayan-Tibetan orogen exerted a strong control over the Cenozoic strain history and strain distribution. The presence of widespread Triassic flysch complex in the Songpan-Ganzi-Hoh Xil and the Qiangtang terranes can be spatially correlated with Cenozoic volcanism and thrusting in central Tibet. The marked difference in seismic properties of the crust and the upper mantle between southern and central Tibet is a manifestation of both Mesozoic and Cenozoic tectonics. The form...

Geologic Evolution of the Himalayan-Tibetan Orogen

Global positioning system velocities from 553 control points within the Tibetan Plateau and on its margins show that the present-day tectonics in the plateau is best described as deformation of a continuous medium, at least when averaged over distances of .;100 km. Deformation occurs throughout the plateau interior by ESE-WNW extension and slightly slower NNE-SSW shortening. Relative to Eurasia, material within the plateau interior moves roughly eastward with speeds that increase toward the east, and then flows southward around the eastern end of the Himalaya. Crustal thickening on the northeast- ern and eastern margins of the plateau occurs over a zone ;400 km wide and cannot be the result of elastic strain on a single major thrust fault. Shortening there accommodates much of India's penetration into Eurasia. A description in terms of movements of rigid blocks with elastic strain associated with slip on faults between them cannot match the velocity field.

Continuous deformation of the Tibetan Plateau from global positioning system data

Global Positioning System (GPS) measurements in China indicate that crustal shortening accommodates most of India's penetration into Eurasia. Deformation within the Tibetan Plateau and its margins, the Himalaya, the Altyn Tagh, and the Qilian Shan, absorbs more than 90% of the relative motion between the Indian and Eurasian plates. Internal shortening of the Tibetan plateau itself accounts for more than one-third of the total convergence. However, the Tibetan plateau south of the Kunlun and Ganzi-Mani faults is moving eastward relative to both India and Eurasia. This movement is accommodated through rotation of material around the eastern Syntaxis. The North China and South China blocks, east of the Tibetan Plateau, move coherently east-southeastward at rates of 2 to 8 millimeters per year and 6 to 11 millimeters per year, respectively, with respect to the stable Eurasia.

https://science.sciencemag.org/content/sci/294/5542/574.full.pdf

Present-Day Crustal Deformation in China Constrained by Global Positioning System Measurements

[1] We present a new global model for Recent plate velocities, REVEL, describing the relative velocities of 19 plates and continental blocks. The model is derived from publicly available space geodetic (primarily GPS) data for the period 1993–2000. We include an independent and rigorous estimate for GPS velocity uncertainties to assess plate rigidity and propagate these uncertainties to the velocity estimates. The velocity fields for North America, Eurasia, and Antarctica clearly show the effects of glacial isostatic adjustment, and Australia appears to depart from rigid plate behavior in a manner consistent with the mapped intraplate stress field. Two thirds of tested plate pairs agree with the NUVEL-1A geologic (3 Myr average) velocities within uncertainties. Three plate pairs (Caribbean–North America, Caribbean–South America, and North America–Pacific) exhibit significant differences between the geodetic and geologic model that may reflect systematic errors in NUVEL-1A due to the use of seafloor magnetic rate data that do not reflect the full plate rate because of tectonic complexities. Most other differences probably reflect real velocity changes over the last few million years. Several plate pairs (Arabia–Eurasia, Arabia–Nubia, Eurasia–India) move more slowly than the 3 Myr NUVEL-1A average, perhaps reflecting long-term deceleration associated with continental collision. Several other plate pairs, including Nazca–Pacific, Nazca–South America and Nubia–South America, are experiencing slowing that began ∼25 Ma, the beginning of the current phase of Andean crustal shortening.

/pdf/revel-a-model-for-recent-plate-velocities-from-space-geodesy-18oq1lu9ey.pdf

REVEL: A model for Recent plate velocities from space geodesy

We process rigorously GPS data observed during the past 25 years from continental China to derive site secular velocities. Analysis of the velocity solution leads to the following results. (a) The deformation field inside the Tibetan plateau and Tien Shan is predominantly continuous, and large deformation gradients only exist perpendicular to the Indo‐Eurasian relative plate motion and are associated with a few large strike‐slip faults. (b) Lateral extrusions occur on both the east and west sides of the plateau. The westward extrusion peaks at ~6 mm/yr in the Pamir‐Hindu Kush region. A bell‐shaped eastward extrusion involves most of the plateau at a maximum rate of ~20 mm/yr between the Jiali and Ganzi‐Yushu faults, and the pattern is consistent with gravitational flow in southern and southeastern Tibet where the crust shows widespread dilatation at 10–20 nanostrain/yr. (c) The southeast borderland of Tibet rotates clockwise around the eastern Himalaya syntaxis, with sinistral and dextral shear motions along faults at the outer and inner flanks of the rotation terrane. The result suggests gravitational flow accomplished through rotation and translation of smaller subblocks in the upper crust. (d) Outside of the Tibetan plateau and Tien Shan, deformation field is block‐like. However, unnegligible internal deformation on the order of a couple of nanostrain/yr is found for all blocks. The North China block, under a unique tectonic loading environment, deforms and rotates at rates significantly higher than its northern and southern neighboring blocks, attesting its higher seismicity rate and earthquake hazard potential than its neighbors.

Present‐Day Crustal Deformation of Continental China Derived From GPS and Its Tectonic Implications

Global Positioning System (GPS) measurements collected since the early 90's allow us to derive geodetic velocities at 16 permanent stations in east Asia and 68 campaign mode sites in north China. The resulting velocity field shows the following: (1) Contrary to the early inferences that the Shanxi Rift has accommodated significant right-slip motion, our results suggest that the rift system, at least in its northern part in north China, is under ESE-WNW extension at a rate of 4±2 mm/yr. The velocity field also suggests that an ESE-WNW trending left-lateral shear zone deforming at a rate of 2±1 mm/yr may exist along the north rim of north China at the latitude of ∼40°N, separating actively extending north China in the south from relatively stable Mongolia in the north. (2) Central and east China move at a rate of 8–11 mm/yr east-southeast with respect to Siberia, implying that the overall east-southeastward motion is the dominant mode of deformation in east China. (3) The India plate moves at a rate of 6±1 mm/yr slower than the NUVEL-1A model prediction relative to the Eurasia plate. (4) Significant eastward motion (20±2 mm/yr) with respect to Siberia occurs in southeastern Tibet. About half of this eastward motion (∼11 mm/yr) is absorbed by structures along the eastern boundary of the Tibetan Plateau.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999JB900391

Contemporary crustal deformation in east Asia constrained by Global Positioning System measurements

Exploring the occurrence of shale oil is of guiding significance to the exploration and recovery of shale oil. However, most studies focus on adsorption and neglect absorption or study it independently, which weakens the understanding of the coupling relationship between adsorption and absorption and the occurrence mechanism of shale oil in kerogen and its associated pores. Based on molecular dynamics (MD) simulation, the kerogen matrix with a smooth surface is constructed, and the general amber force field is adopted to calculate the adsorption and absorption of shale oil in a type II kerogen slit, and the influences of temperature, pressure, and pore diameter on the occurrence of shale oil are also discussed. Molecules absorbed in the kerogen matrix are mainly retained in the free space formed by the accumulation of aliphatic carbon. The effects of temperature on the distribution of shale oil in adsorption and absorption are opposite. High temperature improves the desorption of molecules from the adsorption sites and causes a lower adsorption and greater absorption. In contrast, pressure and pore diameter only slightly influence the distribution of shale oil. Unexpectedly, the result under aqueous conditions shows that the shale oil was absorbed quickly before the formation of water clusters. Once the water clusters are formed due to the strong hydrogen bonding and adsorbed near the N-, S-, and O-containing groups on the kerogen surface, the matrix gaps are blocked due to the size exclusion, and the absorption is suppressed. Additionally, we established the evolution of the ratio of free-adsorbed–absorbed oil at different temperatures and pressures, which provides a new idea and a new method for detecting the occurrence and mobility evaluation of shale oil under reservoir conditions. 

Molecular Dynamics Simulation of Adsorption and Absorption Behavior of Shale Oil in Realistic Kerogen Slits

One of the most striking geologic features of the Pamir is the south-dipping lithospheric slab beneath the orogen characterized by an intracontinental Wadati-Benioff zone. A widely accepted hypothesis over the past 40 years interprets the slab to represent southward subducted cratonic Asian continental lithosphere, which predicts significant cratonic Asia-sourced crustal materials (e.g., Tarim Basin) beneath the Pamir. Alternatively, recent studies have interpreted the slab to be lithosphere delaminated from the base of the Pamir. To test these hypotheses, depth-tectonic affinity relations of crustal xenoliths carried by Miocene volcanic rocks in the eastern Pamir, interpreted to be sourced from the Pamir deep lithosphere, are used to determine whether they represented Asian affinity cratonic crust. Thermodynamic calculations, zircon U-Pb geochronology combined with rare earth element analysis, and whole-rock major-trace element and Sr-Nd isotopic analyses document that: 1) eclogite and pyroxenite xenoliths (~31–43 kbar/ ~960–1170°C) are the deepest sourced portions of the lithosphere from ~100–140 km depth, the protoliths of which represent the mid-lower crustal rocks of the Cretaceous Pamir magmatic arc, rather than material from cratonic Asia; and 2) granulite xenoliths (~20 kbar/~900°C) represent the Cenozoic lower crustal rocks of Pamir terranes from ~70 km depth. These results indicate the south-dipping slab represents delaminated Pamir lower crust and mantle lithosphere, rather than intracontinental subduction of Asian lithosphere and further support the hypothesis of minimal Cenozoic northward translation of the Pamir. 

Was Cratonic Asia Deeply Subducted beneath the Pamir? Evidence from P‐T Conditions and Tectonic Affinities of Cenozoic Pamir Crustal Xenoliths

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Contemporary crustal deformation in east Asia constrained by Global Positioning System measurements

Molecular Dynamics Simulation of Adsorption and Absorption Behavior of Shale Oil in Realistic Kerogen Slits

Was Cratonic Asia Deeply Subducted beneath the Pamir? Evidence from P‐T Conditions and Tectonic Affinities of Cenozoic Pamir Crustal Xenoliths