Late Oligocene-Miocene intra-continental mountain building of the Harke Mountains, southern Chinese Tian Shan: Evidence from detrital AFT and AHe analysis

2020 ◽  
Vol 191 ◽  
pp. 104198
Author(s):  
Yingying Jia ◽  
Jimin Sun ◽  
Lixing Lü ◽  
Jianzhang Pang ◽  
Ying Wang
2021 ◽  
Author(s):  
Siyu Wang ◽  
Edwin Nissen ◽  
Timothy Craig ◽  
Eric Bergman ◽  
Léa Pousse-Beltran

The Kepingtag (Kalpin) fold-and-thrust belt of the southern Chinese Tian Shan is characterized by active shortening and intense seismic activity. Geological cross-sections and seismic reflection profiles suggest thin-skinned, northward-dipping thrust sheets detached in an Upper Cambrian décollement. The January 19 2020 Mw 6.0 Jiashi earthquake provides an opportunity to investigate how coseismic deformation is accommodated in this structural setting. Coseismic surface deformation resolved with Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) is centered on the back limb of the frontal Kepingtag anticline. Elastic dislocation modelling suggests that the causative fault is located at ~7 km depth and dips ~7° northward, consistent with the inferred position of the décollement. The narrow slip pattern (length ~37 km but width only ~9 km) implies that there is a strong structural or lithological control on the rupture extent, with up-dip slip propagation possibly halted by an abrupt change in dip angle where the Kepingtag thrust is inferred to branch off the décollement. A depth discrepancy between mainshock slip constrained by InSAR and teleseismic waveform modelling (~7 km) and well-relocated aftershocks (~10-20 km) may imply that sediments above the décollement are velocity strengthening. We also relocate 148 regional events from 1977 to 2020 to characterize the broader distribution of seismicity across the Kepingtag belt. The calibrated hypocenters combined with previous teleseismic waveform models show that thrust and reverse faulting earthquakes cluster at relatively shallow depths of ~7-15 km but include abundant out-of-sequence events both north and south of the frontal Kepingtag fault.


Geology ◽  
1994 ◽  
Vol 22 (6) ◽  
pp. 487 ◽  
Author(s):  
Marc S. Hendrix ◽  
Trevor A. Dumitru ◽  
Stephan A. Graham

2019 ◽  
Vol 766 ◽  
pp. 416-432 ◽  
Author(s):  
Jian Chang ◽  
Dan Li ◽  
Kyoungwon Min ◽  
Nansheng Qiu ◽  
Yao Xiao ◽  
...  

Tectonics ◽  
1998 ◽  
Vol 17 (1) ◽  
pp. 1-27 ◽  
Author(s):  
A. Yin ◽  
S. Nie ◽  
P. Craig ◽  
T. M. Harrison ◽  
F. J. Ryerson ◽  
...  

Geology ◽  
2020 ◽  
Vol 48 (7) ◽  
pp. 728-732 ◽  
Author(s):  
Xin Wang ◽  
Barbara Carrapa ◽  
Yuchen Sun ◽  
David L. Dettman ◽  
James B. Chapman ◽  
...  

Abstract Interactions between midlatitude westerlies and the Pamir–Tian Shan mountains significantly impact hydroclimate patterns in Central Asia today, and they played an important role in driving Asian aridification during the Cenozoic. We show that distinct west-east hydroclimate differences were established over Central Asia during the late Oligocene (ca. 25 Ma), as recorded by stable oxygen isotopic values of soil carbonates. Our climate simulations show that these differences are present when relief of the Pamir–Tian Shan is higher than 75% of modern elevation (∼3000 m). Integrated with geological evidence, we suggest that a significant portion of the Pamir–Tian Shan orogen had reached elevations of ∼3 km and acted as a moisture barrier for the westerlies since ca. 25 Ma.


2021 ◽  
Author(s):  
Xin Wang ◽  
Barbara Carrapa ◽  
Xu Zhang ◽  
Ilhomjon Oimuhammadzoda ◽  
Fahu Chen

<p>The Cenozoic Asian aridification has been related to the retreat of the Paratethys, the uplift of the Tibet, and/or global cooling. However, the details of the mechanisms responsible for this paleoclimate shift remain poorly constrained. Modern observations indicate that interactions between mid-latitude westerlies and the Pamir-Tian Shan Mountains significantly impact hydroclimate patterns in central Asia today, and may have played an important role in driving Asian aridification during the Cenozoic. However, the timing when this topographic-atmospheric framework was established remains poorly constrained.</p><p>Here, we present magnetostratigraphy, U-Pb geochronology, thermochronology, paleoclimatology, stable carbon and oxygen isotope geochemistry, and climate modelling techniques to the Cenozoic sedimentary sequences in the Tajik Basin. Our results show that: 1) the penultimate and ultimate retreat of the Paratethys from central Asia occurred at ~41 and ~37.4 Ma, respectively; 2) the Pamirs have experienced active deformation and accelerated exhumation during the late Oligocene to early Miocene; 3) the windward (western) side of the Pamir and Tian Shan has been characterized by a wetter climate changes, whereas, the leeward (eastern) side of the orogen has been characterized by more arid conditions since the Late Oligocene; 4)  This distinct east-west hydroclimate differences, when integrated with climate modeling results, suggests that at least part of the Pamir-Tian Shan mountains had reached elevations ≥ 3 km and acted as a moisture barrier for the westerlies since ~25 Ma. We suggest that the interactions between the westerlies and the Pamir-Tian Shan orogen played an important role in driving Asian aridification since the Late Oligocene.</p>


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