{"title":"The Crust-Mantle Interaction of the Qiangtang Terrane: New evidence from the Effective Elastic Thickness of the Lithosphere","authors":"Qiang Li, Wenna Zhou, Bohu Xu, Yongkang Chan, Hai Tang, Yunmeng Wu","doi":"10.1016/j.tecto.2024.230510","DOIUrl":null,"url":null,"abstract":"<div><div>The crust-mantle interaction in the Qiangtang terrane is significant to study continental rheology and evolution. Its mechanism remains a subject of considerable debate for the reason of lack of sufficient geophysical evidence. The effective elastic thickness (<em>T<sub>e</sub></em>) of the lithosphere can provide important constraints on this issue because it is sensitive to the state of mechanical coupling between the crust and the lithospheric mantle. We present new high-resolution <em>T<sub>e</sub></em> of the Qiangtang terrane by using the multitaper admittance method with fusion of different window, based on satellite gravity and topographical data. Thus, a detailed study of the lithosphere is conducted, for the first time to utilize the spatial variations of <em>T<sub>e</sub></em> and associated parameters, including thermal structures of the lithosphere, uppermost mantle seismic Pn-velocity, and crustal deformation. The results indicate that crust-mantle interaction in the Qiangtang terrane primarily occurs in the middle Qiangtang terrane (87°E ∼ 95°E, 32°N ∼ 34°N), where Te values are lower. In the eastern and western Qiangtang terrane, <em>T<sub>e</sub></em> values are higher, implying weaker late-stage modification. Due to Rayleigh-Taylor instability, lithospheric delamination occurred beneath the south Qiangtang terrane. Based on the extent of these low <em>T<sub>e</sub></em> values (<em>T<sub>e</sub></em> < 50 km), we conclude that the delaminated lithospheric slab sinking into the mantle is ∼400 km in length and elongated in shape. The delamination induces the upwelling of mantle material, upward stress, volcanic activity, extensional faults, and hot springs in the Qiangtang terrane.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"890 ","pages":"Article 230510"},"PeriodicalIF":2.7000,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tectonophysics","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0040195124003123","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}
引用次数: 0
Abstract
The crust-mantle interaction in the Qiangtang terrane is significant to study continental rheology and evolution. Its mechanism remains a subject of considerable debate for the reason of lack of sufficient geophysical evidence. The effective elastic thickness (Te) of the lithosphere can provide important constraints on this issue because it is sensitive to the state of mechanical coupling between the crust and the lithospheric mantle. We present new high-resolution Te of the Qiangtang terrane by using the multitaper admittance method with fusion of different window, based on satellite gravity and topographical data. Thus, a detailed study of the lithosphere is conducted, for the first time to utilize the spatial variations of Te and associated parameters, including thermal structures of the lithosphere, uppermost mantle seismic Pn-velocity, and crustal deformation. The results indicate that crust-mantle interaction in the Qiangtang terrane primarily occurs in the middle Qiangtang terrane (87°E ∼ 95°E, 32°N ∼ 34°N), where Te values are lower. In the eastern and western Qiangtang terrane, Te values are higher, implying weaker late-stage modification. Due to Rayleigh-Taylor instability, lithospheric delamination occurred beneath the south Qiangtang terrane. Based on the extent of these low Te values (Te < 50 km), we conclude that the delaminated lithospheric slab sinking into the mantle is ∼400 km in length and elongated in shape. The delamination induces the upwelling of mantle material, upward stress, volcanic activity, extensional faults, and hot springs in the Qiangtang terrane.
期刊介绍:
The prime focus of Tectonophysics will be high-impact original research and reviews in the fields of kinematics, structure, composition, and dynamics of the solid arth at all scales. Tectonophysics particularly encourages submission of papers based on the integration of a multitude of geophysical, geological, geochemical, geodynamic, and geotectonic methods