{"title":"从地震面波层析成像看青藏高原受峨眉山大火成岩强区限制的东南挤压作用","authors":"Yuanyuan V. Fu , Lun Li , Junwei Ma , Nannan Sun","doi":"10.1016/j.pepi.2024.107153","DOIUrl":null,"url":null,"abstract":"<div><p>Active deformation is ongoing in the southeastern margin of the Tibetan Plateau due to the collision of the Indian and Eurasian continents. While large-scale motion of the surface occurs, the nature of deformation at depth remains unresolved. We construct new lithospheric seismic anisotropic (radially and azimuthally) and shear-wave velocity models using fundamental-mode Rayleigh- and Love-wave phase velocity at periods of 20–100 s obtained from the ChinArray experiment to constrain the deformation style of the crust and upper mantle in the southeastern margin of the Tibetan Plateau. The results show that the uppermost mantle (Moho-90 km) underneath the Tibetan Plateau and northwestern part of the western Yangtze block are characterized with NE-SW oriented azimuthal anisotropy, prominent slow velocity and negative radial anisotropy (V<sub>SH</sub> < V<sub>SV</sub>). We interpret that this seismic pattern reflects the southeastward extrusion of the Tibetan uppermost mantle that may thermally erode the northwestern edge and result in the vertically coherent fabric due to the barriers of the left strong Emeishan large igneous province (i.e., south of the western Yangtze block) dominated by the high shear wave velocities. Low velocity anomaly, N-S trending azimuthal anisotropy, and negative radial anisotropy in the uppermost mantle beneath the eastern Yangtze block are most probably associated with vertical migration of hot mantle material from the lithosphere delamination and/or a branch of the Hainan plume.</p></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"348 ","pages":"Article 107153"},"PeriodicalIF":2.4000,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Southeastward extrusion of the Tibetan Plateau limited by the strong Emeishan large igneous province from earthquake surface wave tomography\",\"authors\":\"Yuanyuan V. Fu , Lun Li , Junwei Ma , Nannan Sun\",\"doi\":\"10.1016/j.pepi.2024.107153\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Active deformation is ongoing in the southeastern margin of the Tibetan Plateau due to the collision of the Indian and Eurasian continents. While large-scale motion of the surface occurs, the nature of deformation at depth remains unresolved. We construct new lithospheric seismic anisotropic (radially and azimuthally) and shear-wave velocity models using fundamental-mode Rayleigh- and Love-wave phase velocity at periods of 20–100 s obtained from the ChinArray experiment to constrain the deformation style of the crust and upper mantle in the southeastern margin of the Tibetan Plateau. The results show that the uppermost mantle (Moho-90 km) underneath the Tibetan Plateau and northwestern part of the western Yangtze block are characterized with NE-SW oriented azimuthal anisotropy, prominent slow velocity and negative radial anisotropy (V<sub>SH</sub> < V<sub>SV</sub>). We interpret that this seismic pattern reflects the southeastward extrusion of the Tibetan uppermost mantle that may thermally erode the northwestern edge and result in the vertically coherent fabric due to the barriers of the left strong Emeishan large igneous province (i.e., south of the western Yangtze block) dominated by the high shear wave velocities. Low velocity anomaly, N-S trending azimuthal anisotropy, and negative radial anisotropy in the uppermost mantle beneath the eastern Yangtze block are most probably associated with vertical migration of hot mantle material from the lithosphere delamination and/or a branch of the Hainan plume.</p></div>\",\"PeriodicalId\":54614,\"journal\":{\"name\":\"Physics of the Earth and Planetary Interiors\",\"volume\":\"348 \",\"pages\":\"Article 107153\"},\"PeriodicalIF\":2.4000,\"publicationDate\":\"2024-02-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physics of the Earth and Planetary Interiors\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0031920124000116\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics of the Earth and Planetary Interiors","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0031920124000116","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Southeastward extrusion of the Tibetan Plateau limited by the strong Emeishan large igneous province from earthquake surface wave tomography
Active deformation is ongoing in the southeastern margin of the Tibetan Plateau due to the collision of the Indian and Eurasian continents. While large-scale motion of the surface occurs, the nature of deformation at depth remains unresolved. We construct new lithospheric seismic anisotropic (radially and azimuthally) and shear-wave velocity models using fundamental-mode Rayleigh- and Love-wave phase velocity at periods of 20–100 s obtained from the ChinArray experiment to constrain the deformation style of the crust and upper mantle in the southeastern margin of the Tibetan Plateau. The results show that the uppermost mantle (Moho-90 km) underneath the Tibetan Plateau and northwestern part of the western Yangtze block are characterized with NE-SW oriented azimuthal anisotropy, prominent slow velocity and negative radial anisotropy (VSH < VSV). We interpret that this seismic pattern reflects the southeastward extrusion of the Tibetan uppermost mantle that may thermally erode the northwestern edge and result in the vertically coherent fabric due to the barriers of the left strong Emeishan large igneous province (i.e., south of the western Yangtze block) dominated by the high shear wave velocities. Low velocity anomaly, N-S trending azimuthal anisotropy, and negative radial anisotropy in the uppermost mantle beneath the eastern Yangtze block are most probably associated with vertical migration of hot mantle material from the lithosphere delamination and/or a branch of the Hainan plume.
期刊介绍:
Launched in 1968 to fill the need for an international journal in the field of planetary physics, geodesy and geophysics, Physics of the Earth and Planetary Interiors has now grown to become important reading matter for all geophysicists. It is the only journal to be entirely devoted to the physical and chemical processes of planetary interiors.
Original research papers, review articles, short communications and book reviews are all published on a regular basis; and from time to time special issues of the journal are devoted to the publication of the proceedings of symposia and congresses which the editors feel will be of particular interest to the reader.