Superposition of structures in the Sichuan‒Yunnan N-S tectonic belt at the eastern margin of the Tibetan Plateau: constraints from structures and magnetic fabrics

Chen, Yingtao; Zhang, Guowei; Lu, Rukui; Xie, Jin-Qiang

doi:10.1007/s12303-014-0050-6

Cited by 3 publications

(4 citation statements)

References 30 publications

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“…At the period of 4-30 s, the area near PZH exhibits high phase velocity anomaly (Figure 8C), which is in good agreement with the Frontiers in Earth Science frontiersin.org characteristics of high Poisson's ratio, high wave velocity, high resistivity, high density, positive magnetic anomaly, and low terrestrial heat flow (Chen et al, 2015;Wang et al, 2017;Wu et al, 2013;Cheng et al, 2017;Shen et al, 2015;Xu et al, 2015;Teng et al, 2019), all distributed in the inner core of the Emeishan large igneous rock province. Moreover, the FPDs in the vicinity of PZH have the characteristics of the NS direction at 4-30 s periods.…”

Section: Crustal Structure Characteristics and Deformation Mechanism ...supporting

confidence: 78%

Characteristics of azimuthal anisotropy in SE Tibetan plateau and its relationship with the background of block structure

Liu

Fang

et al. 2023

Front. Earth Sci.

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The southeastern Tibetan Plateau, which includes the Tibetan Plateau, Yangtze Block, and Cathaysia Block, is geotectonically situated in the compound part of the Tethys-Himalayan tectonic domain and the Peninsular Pacific tectonic domain. It is one of the critical regions for studying the scientific problems of plateau material lateral escape, lithosphere deformation, geotectonic properties of blocks, and deep dynamics. In this study, we use ambient noise data recorded by 401 broadband stations to obtain high-resolution short-period (T = 4–32 s) Rayleigh wave azimuthally anisotropic phase velocity maps. These could provide fresh clues for an in-depth understanding of the crust-mantle velocity structure, deformation mechanism, and geotectonic evolution in the southeastern Tibetan Plateau. Within the Simao block, the strikes of the faults and the orientations of the principal compressive stress of the stress field both generally coincide with the fast-wave polarization direction (FPD). The FPD near the Lancangjiang fault zone in the west is in the NE-SW direction, near the Wuliangshan fault zone in the center is near the NS direction, and near the Red River fault zone in the east is the NW-SE direction. We estimate that the compressive stress in the southwest direction of the Tibetan Plateau material has a controlling effect on the crustal deformation of the Simao block, which is likewise blocked by the Lincang granite belt, resulting in strong tectonic deformation. The FPD of the crust in the middle Red River fault zone is NS direction, significantly different from the fault strike. Combining with the seismic activity and GPS results, the depth of 8 km below the surface of the middle Red River fault is completely locked, and we conclude that the anisotropy of the upper crust of the middle part of the Red River fault zone is related to the action of the regional tectonic stress field. Taking into account geochemical and thermochemical results, we speculate that the complex tectonic stress at the junction of the blocks leads to prominent regional characteristics of the FPDs of azimuthal anisotropy in the crust, suggesting that the Shizong-Mile fault zone may be the western boundary between the Yangtze block and the Cathaysia block.

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Section: Crustal Structure Characteristics and Deformation Mechanism ...supporting

confidence: 78%

Characteristics of azimuthal anisotropy in SE Tibetan plateau and its relationship with the background of block structure

Liu

Fang

et al. 2023

Front. Earth Sci.

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“…The Shimian area extended along the weak crust zone that formed earlier from the Anninghe Fault, Daliangshan Fault, Zemuhe Fault, and Xiaojiang Fault, creating the present Xianshuihe–Anninghe–Zemuhe–Xiaojiang sinistral strike‐slip fault system. However, the Daliangshan Fault may have been the result of straightening the arc strike‐slip system in the later stage, which revived the Daliangshan Fault and changed from the earlier thrusting to the present sinistral shear deformation (Chen, Zhang, Lu, & Xie, 2015).…”

Section: Discussionmentioning

confidence: 99%

Formation and evolution of Xianshuihe Fault Belt in the eastern margin of the Tibetan Plateau: Constraints from structural deformation and geochronology

Chen

Zhang

et al. 2020

Geological Journal

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The Xianshuihe Fault Belt (XSF), along which the syntectonic Zheduoshan batholith was emplaced, has great significance for the reconstruction of the tectonic framework in the eastern margin of the Tibetan Plateau. In this contribution, formation process and evolution of the XSF are discussed based on the structural deformation in the field and the geochronology of Zheduoshan batholith. The results show that the XSF current arc‐shaped protrusion to the north‐east probably was formed by a fracture of the clockwise rotation compression that extended northward to the periphery with the eastern Himalayan tectonic syntaxis as the centre. It is a complex fault belt formed by the superposition of multi‐stage structures. In the early‐stage formation and evolution of the XSF, the Oligocene‐Miocene migmatite zone and Miocene granites of the Zheduoshan batholith were emplaced. Among them, the lower limit of the XSF's initial activity time was not less than 47 Ma that was limited by the Zircon U–Pb geochronology of migmatite zone formed under the compression system. During the emplacement of Miocene granites, the XSF underwent a process from compression to sinistral strike‐slip, and the geochronology indicates that the onset of the XSF sinistral strike slip should not be less than 14 Ma. After syntectic magmatism, the XSF also experienced the shear deformation (from ductile to brittle) with sinistral kinematics. 40Ar‐39Argeochronology results show that the ductile shear deformation mainly occurred around 5.5–3.2 Ma and accompanied a staged and differential uplift from north to south. It extended to the south along the weak crustal zone of Anninghe, Daliangshan, Xiaojiang, and other faults, forming the Xianshuihe–Anninghe–Xiaojiang sinistral strike‐slip fault system on the eastern margin of the Tibetan Plateau, and large‐scale sinistral strike slip began around 5 Ma. Our new insights lay a foundation for understanding and dissecting the formation and evolution of the Tibetan Plateau eastern margin.

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“…paramagnetic minerals to the susceptibility of the sample, such as biotite and other silicate minerals (Chadima, Hrouda, & Melichar, 2006; Y. T. Chen et al, 2015). As previously mentioned, the lithology of the Qionglai-Changshiba profile sample is mainly lithic quartz sandstone, quartz sandstone, and feldspar quartz sandstone.…”

Section: Bulk Susceptibilitymentioning

confidence: 98%

“…The LMS extends south to the Sichuan-Yunnan N-S trending tectonic belt, forming a "Y-shaped" tectonic pattern. The Daliangshan fault system and the Xianshuihe fault belt are typical structural systems with a trend from NW to N-S on the eastern margin of the Tibetan Plateau (Figure 2b), which were formed in the Cenozoic (Y. T. Chen et al, 2015Chen et al, , 2020. Therefore, the NW-trending structures in the FBSL, including the Shuangshi Fault, are the result of superimposed deformations with the Sichuan-Yunnan N-S-trending tectonic belt, to a certain extent.…”

Section: Nw-se Trending Structures Have Been Developed Only In the Southernmentioning

confidence: 99%

Structural analysis of the foreland basin of the southern Longmenshan tectonic belt: New insights from magnetic fabrics

Chen

et al. 2021

Geological Journal

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Multi‐scale intracontinental deformations were developed in response to the tectonic evolution of the southern Longmenshan tectonic belt (LMS) on the eastern margin of the Tibetan Plateau. Detailed studies, including field structural analysis and anisotropy of magnetic susceptibility (AMS), were conducted on sedimentary rocks in the foreland basin of the southern Longmenshan tectonic belt (FBSL) in order to better understand the tectonic evolution of the southern LMS. Field observations show that FBSL deformations are mainly characterized by broad and gentle folds in a NE–SW direction and shallow thrust faults. At least two sedimentary discontinuities and two‐stage deformations occurred after the deposition of Cretaceous strata. Samples of magnetic fabrics from the Qionglai–Changshiba profile were characterized by the triaxial magnetic susceptibility ellipsoids common in sedimentary rocks. The magnetic fabrics of the profile represent a weak deformation that was associated with layer‐parallel shortening before folding and mainly reflect the Mesozoic–Cenozoic NW–SE convergence. There are also the following atypical magnetic fabrics: magnetic foliation that is oblique to the bedding and that was associated with layer‐parallel simple shearing during folding; and magnetic lineation that is to varying degrees oblique to the strike of bedding and represents a superposition of structures. Based on the correlation results of magnetic fabrics for samples of different ages, a tectonic superposition since the Late Indosinian Orogeny was found in FBSL. By combining field structural analysis and magnetic fabrics, it was suggested herein that the FBSL is a propagation product of Mesozoic–Cenozoic deformations of southern LMS to the southeast, which therefore experienced a composite superposition of deformations. This finding provides the basis for a comprehensive understanding of the southern LMS and may shed light on the uplift of the eastern margin of the Tibetan Plateau and the tectonic response of its eastern boundary.

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Superposition of structures in the Sichuan‒Yunnan N-S tectonic belt at the eastern margin of the Tibetan Plateau: constraints from structures and magnetic fabrics

Cited by 3 publications

References 30 publications

Characteristics of azimuthal anisotropy in SE Tibetan plateau and its relationship with the background of block structure

Characteristics of azimuthal anisotropy in SE Tibetan plateau and its relationship with the background of block structure

Formation and evolution of Xianshuihe Fault Belt in the eastern margin of the Tibetan Plateau: Constraints from structural deformation and geochronology

Structural analysis of the foreland basin of the southern Longmenshan tectonic belt: New insights from magnetic fabrics

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