Cenozoic Structural Deformation and Mechanisms of Exhumation of the Metamorphic Complexes in Southeastern Tibetan Plateau: Implications for Intraplate Middle-lower Crustal Flow in Response to Continental Collision

Chen, Xiaoyu; Liu, Junlai; Burg, Jean‐Pierre; Yan, Jiaxin; Fan, Wenkui; Zhao, Chao

doi:10.1002/essoar.10505920.1

Cited by 2 publications

(3 citation statements)

References 24 publications

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“…It is still doubtful whether the extension event caused the metamorphic complex to be exposed to the surface. Since the Yulong complex and the Daxiangshan complex in southeastern Tibet were uplifted after 33 Ma (Chen, 2018), we speculate that the ductile detachment event in this period (Eocene) formed, but may not have led to the exposure of, the Jitang metamorphic complex (Fig. 13).…”

Section: Regional and Tectonic Implicationsmentioning

confidence: 96%

“…Through a study of the Ximeng metamorphic complex and the BuKhang metamorphic complex in the Sundaland terrane, Chen (2018) proposed that intraplate deformation was as important and widespread as boundary deformation during the southeast escape of the Sundaland terrane, suggesting that the ductile shear deformation in the Ximeng metamorphic complex was caused by strain localization during the flow of the middle and lower crust. Based on the combined analysis with the kinematic characteristics of the Guoxuepu shear zone, we suggest that the uplift and detachment mechanism of the Jitang metamorphic complex in the Eocene was similar to that of the Ximeng metamorphic complex in the Sundaland terrane, which is consistent with the characteristics of intraplate deformation.…”

Section: Regional and Tectonic Implicationsmentioning

confidence: 99%

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Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

FENG,

WANG,

WANG

et al. 2024

Acta Geologica Sinica (Eng)

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The Jitang metamorphic complex is key for studying the tectonic evolution of the Northern Lancangjiang zone. Through structural–lithological mapping, structural analysis and laboratory testing, the composition of the Jitang metamorphic complex was determined. The macro‐ and microstructural analyses of the ductile detachment shear zone (Guoxuepu ductile shear zone 2–4 km wide) between the metamorphic complex and the overlying sedimentary cap show that the shear sense of the ductile shear zones is top–to–the–southeast. The presence of various deformation features and quartz C–axis electron backscatter diffraction (EBSD) fabric analysis suggests multiple deformation events occurring at different temperatures. The average stress is 25.68 MPa, and the strain rates (έ) range from 9.77×10–14 s–1 to 6.52×10–16 s–1. The finite strain of the Guoxuepu ductile shear zone indicates an elongated strain pattern. The average kinematic vorticity of the Guoxuepu ductile shear zone is 0.88, implying that the shear zone is dominated by simple shear. The muscovite selected from the protomylonite samples in the Guoxuepu ductile shear zone yields a 40Ar–39Ar age of 60.09±0.38 Ma. It is suggested that coeval with the initial Indo–Eurasian collision, the development of strike‐slip faults led to weak and unstable crust. Then, upwelling of lower crust magma induced the detachment of the Jitang metamorphic complex in the Eocene.

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Section: Regional and Tectonic Implicationsmentioning

confidence: 96%

Section: Regional and Tectonic Implicationsmentioning

confidence: 99%

Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

FENG,

WANG,

WANG

et al. 2024

Acta Geologica Sinica (Eng)

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“…Multiple geochronological dates and lower hemisphere equal‐area stereoplots of foliation and mineral stretching lineation are plotted in these two profiles. The geochronological dates from number 1 to 13 are cited from Chen (2018), Liu et al. (2013), Wang et al.…”

Section: Geological Setting and Sample Descriptionmentioning

confidence: 99%

Thermal and Physical Properties of Barrovian Metamorphic Sequence Rocks in the Ailao Shan‐Red River Shear Zone, and Implications for Crustal Channel Flow

Ji,

Liu,

Palin

et al. 2024

JGR Solid Earth

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The collisional history between Greater India and the Eurasian plate has been well constrained by the study of exhumed Barrovian metamorphic sequence (BMS) rocks in the Himalayan Range. However, in the southeastern Tibetan Plateau, the collisional records have been obscured by intense, regional‐scale strike‐slip overprinting and recrystallization. Here, in BMS rocks from the Ailao Shan–Red River shear zone (ARSZ), we report the first discovery of a >250 km long, high‐pressure (high‐P) granulite belt (>1.0 GPa), identified by the presence of relict kyanite and associated decompression reaction textures. Petrological phase equilibrium modeling showed that exposed micaschists in the region represent exhumed middle crust (20–25 km, 600–670°C), while the high‐P granulite rocks are remnants of thickened lower crust (45–55 km, 800–850°C). This indicates that the northeast edge of the ARSZ experienced an additional ∼25 km of uplift and exhumation compared to the southwest side, facilitated by brittle thrusting/imbrication along the Ailao Shan fault (micaschists) and ductile extrusion along the Red River fault (granulite). Geochronological study shows that the upper portion of the BMS preserves older metamorphic ages (52–34 Ma) than the lower portion (32–29 Ma), which was attributed to spatial variation in cooling rates. Using calculated P–T–t–d paths, we also examined variation in density and seismic wave speeds for BMS in the ARSZ. Our data correlate with fieldwork conducted elsewhere within the Himalayan Range indicating that the kyanite to sillimanite transition zone may serve as a “cap” for the horizontal migration of melt within the lower crust.

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Cenozoic Structural Deformation and Mechanisms of Exhumation of the Metamorphic Complexes in Southeastern Tibetan Plateau: Implications for Intraplate Middle-lower Crustal Flow in Response to Continental Collision

Cited by 2 publications

References 24 publications

Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

Thermal and Physical Properties of Barrovian Metamorphic Sequence Rocks in the Ailao Shan‐Red River Shear Zone, and Implications for Crustal Channel Flow

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Cenozoic Structural Deformation and Mechanisms of Exhumation of the Metamorphic Complexes in Southeastern Tibetan Plateau: Implications for Intraplate Middle-lower Crustal Flow in Response to Continental Collision

Cited by 2 publications

References 24 publications

Structural, 40Ar/39Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

Structural, 40Ar/39Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

Thermal and Physical Properties of Barrovian Metamorphic Sequence Rocks in the Ailao Shan‐Red River Shear Zone, and Implications for Crustal Channel Flow

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Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

Structural, ⁴⁰Ar/³⁹Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone