| Autor: |
Li, Jie, Yao, Yuan, Li, Rui, Yusan, Sulitan, Li, Guirong, Freymueller, Jeffrey T., Wang, Qi |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 6/16/2022, Vol. 49 Issue 11, p1-11, 11p |
| Abstrakt: |
Across inherited complex fold‐and‐thrust belts (FTBs), shortening may be accommodated at different rates depending on structural style variations; such cases have rarely been documented We present the example of the Kepingtage FTB in southern Tianshan, which is bisected by the NNW‐trending left‐lateral strike‐slip Piqiang Fault (PQF) into eastern and western segments. The 1.45 ± 0.31–2.10 ± 0.42 mm/a shortening rate of the eastern segment is accommodated in a diffuse‐deformation pattern within the five‐row thrust‐anticlinal zone and the 2.36 ± 0.23–3.70 ± 0.59 mm/a shortening rate of the western segment is accommodated within the two‐row thrust‐anticlinal zone at the FTB front. To accommodate the latitudinal variability, the PQF exhibits a 2.30 ± 0.20–4.10 ± 0.40 mm/a segmentation strike‐slip rate. The 2.35 ± 0.33–4.20 ± 0.45 mm/a shortening rate of the Kepingtage FTB and southern Tianshan Fault is one‐third of the total convergence rate between the Tarim Basin and Kazakh Platform at 77°–79°E; hence, the complex Tianshan deformation occurred mainly at the FTB. Plain Language Summary: The Kepingtage fold‐and‐thrust belt (FTB) in southern Tianshan is a typical imbricated thrust structure divided into eastern and western segments by a NNW‐trending left‐lateral strike‐slip fault (Piqiang Fault; PQF), which regulates inhomogeneous thrusting and shortening rates. The interaction between Kepingtage FTB shortening, PQF shear deformation, and rate accommodation within various thrust‐anticlinal zones remain unclear. Investigating fault kinematics and strain distribution is essential for describing regional deformation images and understanding deformation patterns. Herein, we utilized latest GPS data from 73 stations in Kepingtage FTB and adjacent areas to obtain the current crustal‐movement velocity field in the Kepingtage Block within the Eurasia reference framework. Deformation of the western segment occurs in front of Kepingtage FTB, and the shortening rate is accommodated in these structures. However, deformation and shortening rates of the east segment are diffused in the five‐row thrust‐anticlinal zone. The longitudinal variability can be attributed to inherited structures, wherein shortening is accommodated at different rates based on structure patterns. Our results confirm the deformation rate of active structures and effects of different faults on regional tectonic deformation. Moreover, deformation of the tectonically active foreland of Tianshan can be used as an analog for understanding the tectonic deformation of tectonically active mountain belts. Key Points: GPS data from 73 stations in the Kepingtage fold‐and‐thrust belt (FTB) and adjacent areas reveal the current Kepingtage Block crustal‐movement velocity fieldShortening rate of Kepingtage FTB and adjacent areas is ∼1/3 of the total convergence rate between the Tarim Basin and Kazakh PlatformShortening rates and deformation patterns vary due to the inherited evolution of the Kepingtage imbricate and pre‐existing structures [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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