Magnetotelluric Evidence for Distributed Lithospheric Modification Beneath the Yinchuan-Jilantai Rift System and Its Implications for Late Cenozoic Rifting in Western North China
文献类型：期刊论文
| 作者 | Li, Xin1,2; Chen, Yun1,2; Tian, Xiaobo1; Liu, Shaozhuo3 |
| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
 |
| 出版日期 | 2022-03-01 |
| 卷号 | 127期号:3页码:25 |
| ISSN号 | 2169-9313 |
| DOI | 10.1029/2021JB022585 |
| 英文摘要 | The Yinchuan-Jilantai rift system (YJRS) is a prominent Cenozoic intracontinental rift zone located along the northwestern margin of the Ordos Block in western North China. Although the absence of volcanism indicates a passive origin, the tectonic driving forces and rift-related deep processes remain poorly understood. Here we use newly obtained broadband magnetotelluric (MT) data to image the lithospheric electrical structure along a similar to 500-km-long profile across the YIRS. At middle-lower crustal levels, the resulting model reveals several subvertical, crustal-scale conductors that spatially correlate with the rift-parallel, high-angle normal faults. We attribute these features to a combined effect of saline fluids and partial melt due to recent supply of heat and volatiles into the crust from below. The crustal-penetrating normal faults that were reactivated during extension serve as permeable pathways for deep fluid migration. In the uppermost mantle, a similar to 400-km-wide zone of enhanced conductivity is present and requires the presence of partial melt. We interpret this feature as evidence for lithospheric modification through upwelling and decompressional melting of the volatile-enriched mantle. When compared with the narrow (<100-km-wide) mantle conductors imaged beneath the Shanxi rift system along the eastern margin of the Ordos Block, such a feature indicates the YJRS has experienced a larger extent of lithospheric modification. Combined with additional geologic and geophysical observations, we attribute this essential difference to the inherited lithospheric heterogeneity and the eastward decreasing far-field impacts from the India-Eurasia collision. Plain Language Summary Throughout the Cenozoic, the western North China Craton has undergone widespread extensional deformation, forming large-scale rift systems around the stable Ordos Block (OB). Although these rifts are active today, the tectonic driving forces and related deep processes remain poorly constrained. We use magnetotelluric (MT) data, which are highly sensitive to deep fluid distribution, to investigate the rift-related fluid dynamics beneath the Yinchuan-Jilantai rift system (YJRS) along the northwestern margin of the OB. In deep crust, we find several isolated, subvertical high-conductivity features that spatially correlate with the rift-parallel normal faults, likely representing pathways for deeply sourced fluids. Looking deeper, we identify a similar to 400-km-wide zone of enhanced electrical conductivity in the uppermost mantle, which is interpreted as evidence for lithospheric modification through low-degree melting of the volatile-enriched mantle. By comparing our results with previous MT observations, we find that the lithosphere of the YJRS has undergone a larger extent of modification than that of the Shanxi rift system along the eastern margin of the OB. Such a difference matches with the surface features of the two rift systems and can be attributed to the inherited lithospheric heterogeneity and the eastward decreasing far-field impacts from the India-Eurasia collision. |
| WOS关键词 | UPPER-MANTLE BENEATH ; NE TIBETAN PLATEAU ; ELECTRICAL-CONDUCTIVITY ; CONTINENTAL-CRUST ; EXTRUSION TECTONICS ; RAPID EXHUMATION ; AQUEOUS FLUIDS ; EASTERN CHINA ; ORDOS BLOCK ; MELT |
| 资助项目 | Chinese Academy of Sciences[XDB18000000] ; National Key R&D Program of China[2016YFC0600402] ; National Natural Science Foundation of China[42004063] ; KAUST[BAS/1/1353-01-01] |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000776510500051 |
| 出版者 | AMER GEOPHYSICAL UNION |
| 资助机构 | Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; KAUST ; KAUST ; KAUST ; KAUST ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; KAUST ; KAUST ; KAUST ; KAUST ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; KAUST ; KAUST ; KAUST ; KAUST ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; KAUST ; KAUST ; KAUST ; KAUST |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/105031]  |
| 专题 | 地质与地球物理研究所_岩石圈演化国家重点实验室 |
| 通讯作者 | Li, Xin; Chen, Yun |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing, Peoples R China 2.CAS Ctr Excellence Deep Earth Sci, Guangzhou, Peoples R China 3.King Abdullah Univ Sci & Technol, Phys Sci & Engn Div, Mecca, Saudi Arabia |
| 推荐引用方式 GB/T 7714 | Li, Xin,Chen, Yun,Tian, Xiaobo,et al. Magnetotelluric Evidence for Distributed Lithospheric Modification Beneath the Yinchuan-Jilantai Rift System and Its Implications for Late Cenozoic Rifting in Western North China[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2022,127(3):25. |
| APA | Li, Xin,Chen, Yun,Tian, Xiaobo,&Liu, Shaozhuo.(2022).Magnetotelluric Evidence for Distributed Lithospheric Modification Beneath the Yinchuan-Jilantai Rift System and Its Implications for Late Cenozoic Rifting in Western North China.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,127(3),25. |
| MLA | Li, Xin,et al."Magnetotelluric Evidence for Distributed Lithospheric Modification Beneath the Yinchuan-Jilantai Rift System and Its Implications for Late Cenozoic Rifting in Western North China".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 127.3(2022):25. |
入库方式： OAI收割
来源：地质与地球物理研究所
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