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| DOI | 10.1016/j.tecto.2021.228932 |
| Pn tomography and anisotropic study of the Indian shield and the adjacent regions | |
| Illa B.; Reshma K.S.; Kumar P.; Srinagesh D.; Haldar C.; Kumar S.; Mandal P. | |
| 发表日期 | 2021 |
| ISSN | 00401951 |
| 卷号 | 813 |
| 英文摘要 | High-resolution P-wave velocity and anisotropy structure of the hitherto elusive uppermost mantle beneath the Indian shield and its surrounding regions are presented to unravel the tectonic imprints in the lithosphere. We inverted high quality 19,500 regional Pn phases from 172 seismological stations for 4780 earthquakes at a distance range of 2° to 15° with a mean apparent Pn velocity of 8.22 km/s. The results suggest that the Pn velocity anomalies with fast anisotropic directions are consistent with the collision environments in the Himalaya, Tibetan Plateau, Tarim Basin, and Burmese arc regions. The higher Pn anomalies along the Himalayan arc explicate the subducting cold Indian lithosphere. The cratonic upper mantle of the Indian shield is characterized by Pn velocity of 8.12–8.42 km/s, while the large part of the central Indian shield has higher mantle-lid velocity of ~8.42 km/s with dominant anisotropic value of 0.2–0.3 km/s (~7.5%) suggesting the presence of mafic ‘lava pillow’ related to the Deccan volcanism. The impressions of the rifts and the mobile belts are conspicuous in the velocity anomaly image indicating their deep seated origin. The Pn anisotropy in the Indian shield exhibits a complex pattern and deviates from the absolute plate motion directions derived from the SKS study, demonstrating the presence of frozen anisotropy in the Indian lithospheric uppermost mantle, due to the large scale tectonic deformation after its breakup from the Gondwanaland. Whereas, Pn and SKS anisotropic observations are well consistent in Tarim basin, Tibetan regions, eastern Himalayan syntaxis and the Burmese arc. The modeled anisotropic Pn clearly manifests a lower velocity anomaly bounded by 85°E and 90°E ridges in the southern Bay of Bengal. Further, 85°E ridge spatially separates the BoB lithosphere into faster and slower regions consistent with the body wave tomography and free-air gravity observation. © 2021 |
| 关键词 | AsiaIndian ShieldPn waveSeismic anisotropyTomographyUppermost mantle |
| 英文关键词 | Gravitation; Seismic waves; Structural geology; Tectonics; Tomography; Velocity; Wave propagation; Absolute plate motions; Body-wave tomographies; Complex pattern; Distance ranges; Surrounding regions; Tectonic deformations; Tibetan Plateau; Uppermost mantle; Anisotropy; collision zone; gravity wave; mantle source; P-wave; seismic anisotropy; tectonic evolution; tomography; upper mantle; Indian Shield |
| 语种 | 英语 |
| 来源期刊 | Tectonophysics
 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/207990 |
| 作者单位 | CSIR- National Geophysical Research Institute, Uppal Road, Hyderabad, India |
| 推荐引用方式 GB/T 7714 | Illa B.,Reshma K.S.,Kumar P.,et al. Pn tomography and anisotropic study of the Indian shield and the adjacent regions[J],2021,813. |
| APA | Illa B..,Reshma K.S..,Kumar P..,Srinagesh D..,Haldar C..,...&Mandal P..(2021).Pn tomography and anisotropic study of the Indian shield and the adjacent regions.Tectonophysics,813. |
| MLA | Illa B.,et al."Pn tomography and anisotropic study of the Indian shield and the adjacent regions".Tectonophysics 813(2021). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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