Progressive northward growth of the northern Qilian Shan–Hexi Corridor (northeastern Tibet) during the Cenozoic

Abstract

The uplift processes of the Qilian Shan (northern Tibetan Plateau) play a central role in our understanding of the dynamics of outward and upward growth of Tibet due to sustained convergence of the Indian and Asian plates. We employ apatite fission track chronology and geological mapping to reveal the time and pattern of the deformation along the Qilian Shan. Our results indicate that the emergence of the Tuolai Shan in the central Qilian Shan occurred at 17-14 Ma, that northern Qilian Shan thrusting began at 10-8 Ma, and that the Laojunmiao anticline formed ca. 3.6 Ma. Together with previous results that show that uplift of the southern Qilian Shan began in the Oligocene, we suggest that the Qilian Shan has undergone progressively northward expansion in the Cenozoic due to significant crustal shortening driven by Qilian Shan thrust fault systems.

A Late Miocene Terrestrial Temperature History for the Northeastern Tibetan Plateau's Period of Tectonic Expansion

“…(Zheng et al, ), experienced uplift after ~8 Ma. Such a pattern would be similar to the progressive northward expansion of the NE TP suggested by the apatite fission track records (Zheng et al, ). This differential uplift may explain the decoupling of the sustainable aridification and short‐term uplift events throughout the Mid to Late Miocene.…”

Miocene Range Growth Along the Altyn Tagh Fault: Insights From Apatite Fission Track and (U‐Th)/He Thermochronometry in the Western Danghenan Shan, China

“…Our new thermochronological data combined with published data in the western Danghenan Shan indicate a period of accelerated deformation since the middle Miocene in the southwestern portion of the Qilian Shan. The accelerated deformation in the middle Miocene is observed not only in the southwestern portion of the Qilian Shan but also throughout the rest of the Qilian Shan: (1) Thermochronological data indicate that the northern margin of the Qilian Shan has undergone accelerated exhumation since ~10 Ma (George et al, ; B. Li et al, ; Zheng et al, , ; Zhuang et al, ); (2) a shift in provenance in the Hexi Corridor from the Bei Shan to the north to the northern Qilian Shan to the south, and facies change in the Hexi Corridor suggest that the deformation that created the high topography of the northern Qilian Shan began at the middle Miocene (Bovet et al, ; Wang, Zhang, Pang, et al, ); (3) rapid exhumation of the central Qilian Shan is reported to have occurred since the middle Miocene (Duvall et al, ; D. Yuan et al, , ; Yu et al, ; Zheng et al, ); (4) accelerated exhumation and depositional rates, sediment coarsening, development of growth strata, and climate change attributed to mountain building in the middle Miocene are widespread across the eastern portion of the Qilian Shan east of the Qinghai Lake, such as the Linxia, Xunhua, Guide, and Gonghe basins (see a review in Lease, ); and (5) new thermochronological data and magnetostratigraphy in the southern margin of the Qilian Shan and northern Qaidam Basin suggest that the region has experienced rapid exhumation since the middle Miocene (Fang et al, ; Pang et al, ; W. Wang, Zheng, Zhang, et al, ; Zhuang et al, ; Figure a).…”

“…Wang et al (); 11—Sun et al (); 12—Lin et al (); 13—Zhuang et al (); 14—D. Yuan et al (); 15—Zheng et al (); 16—Bovet et al (); 17—George et al (); 18—Wang, Zhang, Pang, et al (); 19—Zheng et al (); 20—Duvall et al (); 21—Yu et al (); 22—B. Li et al (); 23—W.…”

“…Although a large body of evidence has been accumulated on the timing of deformation in north Tibet (Lease, ; Molnar & Stock, ; Zhuang et al, ) and along the Altyn Tagh fault (e.g., Yin et al, ; F. Cheng et al, , ), the kinematics and dynamics of north Tibet remain highly debated. For example, whether the northern Tibetan Plateau has undergone gradual northward propagation in the Cenozoic (e.g., Bovet et al, ; Burchfiel et al, ; Meyer et al, ; Zheng et al, ) and whether the entire Qilian Shan has experienced a synchronous deformation in the early Cenozoic (Clark, ; Clark et al, ) or middle Miocene (Lease, ; Molnar & Stock, ). The knowledge on deformation timing in the huge area of the Qilian Shan, especially for the southwestern portion of the Qilian Shan, such as the Danghenan Shan, Daxue Shan, and the remote region near the Hala Lake in the interior Qilian Shan, hampers the construction of a holistic deformation model for the northern Tibetan Plateau.…”

Diachronous Growth of the Altyn Tagh Mountains: Constraints on Propagation of the Northern Tibetan Margin From (U‐Th)/He Dating

“…Previous studies have shown that exhumation in the western part of the North Qilian region occurred at ~9 Ma (Zheng et al, ), whereas exhumation in the eastern part of the region occurred at ~24 Ma (Pan et al, ). Exhumation of central Qilian is reported to have occurred at 17–14 Ma, supporting the theory that the Qilian region progressively expanded northward during the Cenozoic (Zheng et al, ). These results are consistent with northward propagation of northern Tibet during the Cenozoic, driven by activity on the thrust faults that merge with the ATFZ (Figure ).…”