Intradecadal Fluctuations and Three‐Dimensional Crustal Kinematic Deformation of the Tianshan and Pamir Derived From Multi‐Geodetic Imaging. Issue 1 (28th December 2022)

• Record Type: Journal Article
• Authors: Pan, Yuanjin; Jiang, Weiping; Ding, Hao; Shum, C. K.; Jiao, Jiashuang; Li, Jiangtao
• Is Part Of: Journal of geophysical research. Volume 128:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-28
• Subjects: GPS imaging -- vertical land deformation -- surface elastic loading deformations -- three‐dimensional crustal deformation of the Tianshan and Pamir -- dynamic tomography; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2022JB025325
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: The uplift of the Tianshan and Pamir Mountains/Areas are caused by active intracontinental tectonic movements. The dynamic mechanism is controversial and has aroused great interest among scholars. In this study, we investigate the present three‐dimensional (3‐D) crustal deformation in the Tianshan and Pamir areas from multi‐geodetic observations from 2002 to 2021. The continuous water deficit throughout Tianshan and Pamir locates mainly in glacier‐covered areas, at a total rate of −0.8 cm w.e./yr, inducing spatial surface uplifting at rates of ∼0.2–0.5 mm/yr. These Global Positioning System (GPS)‐derived velocities in the vertical deformation of the Tianshan and Pamir were corrected based on surface elastic loading models and the Gravity Recovery and Climate Experiment Follow‐On (GRACE/GFO)‐inferred hydrological loading deformation, and interpolated using the GPS imaging method for a higher 3‐D crustal deformation spatial resolution. In conclusion, surface hydrology is one of the driven factors affecting the regional vertical velocity field observed by GPS. The kinematic crustal shortening and vertical tectonic uplift are integrated within different blocks, which illustrate the contemporary dynamics throughout the Tianshan and Pamir. The relevant spatial characteristics between the 3‐D crustal deformation and dynamic tomography along the Tianshan indicate that the relatively weaker lithosphere beneath the central Tianshan is subject to strong compression, which induces the present‐day crustal uplift. Plain Language Summary: The mountain building of Tianshan and its forelands are the remote effect of collision between the Indian and Eurasian plates. As a typical region with intracontinental plate collisions, the Tianshan mountains have complex orogenic processes and geological structures. In this study, multi‐source geodetic observations are used to quantify the three‐dimensional (3‐D) crustal deformation in this region and its surroundings. The integrated surface elastic loading models and GRACE/GFO observations are used to modify the surface elastic loads of vertical land deformation from the GPS coordinate time series spanning from 2002 to 2021. We perform a detailed analysis of the intradecadal fluctuations of the GPS and GRACE/GFO observations. The GPS imaging has been adopted to interpolate 3‐D velocity vectors and tectonic deformation to identify the crustal deformation of Tianshan and Pamir. We compare the observed 3‐D crustal deformation with the dynamic tomography, which could provide a better understanding of the possible mechanisms of crustal uplift along the Tianshan. Key Points: The variation of surface hydrological load induce crustal uplift in the Tianshan and its surroundings constrained by GRACE/GFO mascons The imaged crustal deformation provides three‐dimensional characteristic in kinematics and dynamics throughout the Tianshan and Pamir The weaker lithosphere beneath the central Tianshan is subject to strong compression that contributes to the tectonic uplift of Tianshan