气候变化领域集成服务门户(CCPortal): Slowing Extrusion Tectonics and Accelerated Uplift of Northern Tibet Since the Mid-Miocene

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DOI	10.1029/2023TC007801
	Slowing Extrusion Tectonics and Accelerated Uplift of Northern Tibet Since the Mid-Miocene
	Lu, Haijian; Cao, Xinwen; Malusa, Marco G.; Zhang, Zhiyong; Pan, Jiawei; Li, Haibing
发表日期	2023
ISSN	0278-7407
EISSN	1944-9194
卷号	42 期号:8
英文摘要	Mechanisms of northern Tibet crustal thickening are strongly debated. Here we present a high-resolution and continuous record (24-4.8 Ma) of anisotropy of magnetic susceptibility and paleomagnetic declination from the Dahonggou section in the northern Qaidam Basin, northern Tibet. Our results reveal two major clockwise rotations of the regional paleostress field at similar to 15 Ma (similar to 20 degrees) and similar to 8.4 Ma (similar to 15 degrees), coeval with episodes of mountain building and basin deformation in northern Tibet. We suggest that simultaneous stress field rotation and uplift observed in the study area are related to progressively slowing lateral-extrusion tectonics along boundary-parallel strike-slip faults (Altyn Tagh and Haiyuan faults). The 15 Ma event can be explained by the transition from northeastward to eastward extrusion of northern Tibet materials due to the obstruction of the rigid Alxa block. As deformation keeps migrating toward the east, the 8 Ma event is possibly related to a change from eastward to southeastward extrusion of northeastern Tibet materials as a result of the resistance of the rigid Ordos block. We conclude that Tibetan deformation evolved through successive stages of slowing extrusion tectonics since the mid-Miocene. Deformation was initially localized along pre-existing lithospheric structures, and subsequently more distributed under confining boundary conditions, leading to crustal thickening and uniform uplift of northern Tibet during the late stage of plateau development. Plain Language Summary How northern Tibet evolved as a far-field response to the India-Asian collision remains an open question. Here we present high-resolution and continuous record (24-4.8 Ma) of anisotropy of magnetic susceptibility and paleomagnetic declination from a well-exposed sedimentary section in the northern Qaidam Basin, northern Tibet. The results indicate two significant clockwise rotations (similar to 20 degrees and similar to 15 degrees) of the regional paleostress field at 15 and 8.4 Ma. Interestingly, these two ages are characterized by large-scale mountain building, basin deformation and initiation or slowdown of major strike-slip faulting in northern Tibet. Given that the relatively weak northern Tibet crust is surrounded by several rigid blocks on its northern and eastern sides, we suggest that Tibetan deformation patterns since the mid-Miocene was associated with successive stages of a weakening extrusion process (from NE- to E-directed extrusion at 15 Ma and from E- to SE-directed extrusion at similar to 8 Ma) that exploits pre-existing lithospheric weak zones. This study lend support to the dominant role of strain transfer from localized strike-slip faulting to distributed thickening deformation under confining boundary conditions in raising the crust of northern Tibet uniformly during the late stage of plateau development.
关键词	anisotropy of magnetic susceptibility paleostress field rotation slip partitioning tectonic extrusion northern Tibet
英文关键词	ALTYN-TAGH FAULT; RESOLUTION MAGNETO STRATIGRAPHY; LATE CENOZOIC DEFORMATION; INDIA-ASIA COLLISION; CENTRAL QAIDAM BASIN; QILIAN SHAN; STRIKE-SLIP; NORTHEASTERN MARGIN; HAIYUAN FAULT; NE TIBET
WOS研究方向	Geochemistry & Geophysics
WOS记录号	WOS:001037529900001
来源期刊	TECTONICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282567
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; Ministry of Natural Resources of the People's Republic of China; Southern Marine Science & Engineering Guangdong Laboratory; Southern Marine Science & Engineering Guangdong Laboratory (Guangzhou); China Geological Survey; Chinese Academy of Geological Sciences; Institute of Geomechanics, Chinese Academy of Geological Sciences; University of Milano-Bicocca; Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS
推荐引用方式 GB/T 7714	Lu, Haijian,Cao, Xinwen,Malusa, Marco G.,et al. Slowing Extrusion Tectonics and Accelerated Uplift of Northern Tibet Since the Mid-Miocene[J],2023,42(8).
APA	Lu, Haijian,Cao, Xinwen,Malusa, Marco G.,Zhang, Zhiyong,Pan, Jiawei,&Li, Haibing.(2023).Slowing Extrusion Tectonics and Accelerated Uplift of Northern Tibet Since the Mid-Miocene.TECTONICS,42(8).
MLA	Lu, Haijian,et al."Slowing Extrusion Tectonics and Accelerated Uplift of Northern Tibet Since the Mid-Miocene".TECTONICS 42.8(2023).