| 班公湖—怒江缝合带中段深部电性结构及其构造意义 |
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| 关键词:Bangong–Nujiang Suture Zone magnetotelluric northern Lhasa terrane Qiangtang terrane partial melting |
| 基金项目:“第二次青藏高原综合科学考察研究”项目(编号: 2019QZKK0701);国家自然科学基金项目(编号: 42174094; 41704099; 42174124);中国地质调查局地质调查项目(编号: DD20221647);中国地质科学院基本科研业务费项目(编号: J2015) |
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| Electrical Resistivity Structure in the Vicinity of the Middle Section of the Bangong–Nujiang Suture Zone, Tibet, as Revealed by Magnetotelluric Data |
| The Bangong–Nujiang Suture zone (BNS), a tectonic boundary separating the Lhasa and Qiangtang terranes of the Tibetan Plateau, has had a relatively complex evolutionary history. However, the deep structures and subduction polarity of the BNS remain points of contention. To comprehensively characterize deep structures in the vicinity of the BNS, we employed Magnetotelluric (MT) data along a north-south profile in the middle of the BNS. The MT sounding curves and phase deep electrical resistivity structure in the vicinity of the BNS. The 3D MT inversion shows that there is a significant high-conductivity anomaly in the mid-to-lower crust along the N–S profile. Roughly bounded by the BNS, the conductive anomaly can be subdivided into two parts: the near-horizontal, distributed conductive anomaly beneath the northern Lhasa terrane; and the north-dipping anomaly beneath the Qiangtang terrane, which gradually disappears to the north. Analyzing these results within the context of previous studies, the conductive anomaly may be the result of partial crustal melting; additionally, its electrical resistivity structure is consistent with the variation of the heat flow observed along the N-S profile. Meanwhile, the north-dipping conductive anomaly to the north of the BNS may be indicative of the northward subduction of the Mesozoic Bangong–Nujiang Ocean, whereas the conductive layer to the south of the BNS may be the trace of a small ocean basin with a low underthrusting angle. |
| XUE Shuai,LU Zhan-wu,LIANG Hong-da,LI Wen-hui,WANG Hai-yan.2022.Electrical Resistivity Structure in the Vicinity of the Middle Section of the Bangong–Nujiang Suture Zone, Tibet, as Revealed by Magnetotelluric Data[J].Acta Geoscientica Sinica,43(6):925-935. |
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