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Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance
He, Enyuan; Zhao, Minghui; Qiu, Xuelin; Sibuet, Jean-Claude; Wang, Jian; Zhang, Jiazheng; Zhao, MH (reprint author), Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Marginal Sea Geol, Guangzhou 510301, Guangdong, Peoples R China.
2016
Source PublicationJOURNAL OF ASIAN EARTH SCIENCES
Volume121Pages:139-152
AbstractThe 140-km wide last phase of opening of the South China Sea (SCS) corresponds to a N145 degrees direction of spreading with rift features identified on swath bathymetric data trending N055 degrees (Sibuet et al., 2016). These N055 degrees seafloor spreading features of the East Sub-basin are cut across by a post-spreading volcanic ridge oriented approximately E-W in its western part (Zhenbei-Huangyan seamounts chain). The knowledge of the deep crustal structure beneath this volcanic ridge is essential to elucidate not only the formation and tectonic evolution of the SCS, but also the mechanism of emplacement of the post-spreading magmatism. We use air-gun shots recorded by ocean bottom seismometers to image the deep crustal structure along the N-S oriented G8G0 seismic profile, which is perpendicular to the Zhenbei-Huangyan seamounts chain but located in between the Zhenbei and Huangyan seamounts, where topographic changes are minimum. The velocity structure presents obvious lateral variations. The crust north and south of the Zhenbei-Huangyan seamounts chain is ca. 4-6 km in thickness and velocities are largely comparable with those of normal oceanic crust of Atlantic type. To the south, the Jixiang seamount with a 7.2-km thick crust, seems to be a tiny post-spreading volcanic seamount intruded along the former extinct spreading ridge axis. In the central part, a 1.5-km thick low velocity zone (3.3-3.7 km/s) in the uppermost crust is explained by the presence of extrusive rocks intercalated with thin sedimentary layers as those drilled at IODP Site U1431. Both the Jixiang seamount and the Zhenbei-Huangyan seamounts chain started to form by the intrusion of decompressive melt resulting from the N-S post-spreading phase of extension and intruded through the already formed oceanic crust. The Jixiang seamount probably formed before the emplacement of the E-W post-spreading seamounts chain. (C) 2016 Elsevier Ltd. All rights reserved.
Department[He, Enyuan; Zhao, Minghui; Qiu, Xuelin; Wang, Jian; Zhang, Jiazheng] Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Marginal Sea Geol, Guangzhou 510301, Guangdong, Peoples R China; [Sibuet, Jean-Claude] IFREMER, Ctr Brest, F-29280 Plouzane, France; [Sibuet, Jean-Claude] 44 Rue Cloitre, F-29280 Plouzane, France; [He, Enyuan; Wang, Jian] Univ Chinese Acad Sci, Beijing 100049, Peoples R China ; 边缘海地质
KeywordEast Sub-basin Of The South China Sea Zhenbei Huangyan Seamounts Chain 2-d Crustal Structure Post-spreading Magmatism
Subject AreaGeology
Document Type期刊论文
Identifierhttp://ir.scsio.ac.cn/handle/344004/15436
Collection中科院边缘海地质重点实验室
Corresponding AuthorZhao, MH (reprint author), Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Marginal Sea Geol, Guangzhou 510301, Guangdong, Peoples R China.
Recommended Citation
GB/T 7714
He, Enyuan,Zhao, Minghui,Qiu, Xuelin,et al. Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance[J]. JOURNAL OF ASIAN EARTH SCIENCES,2016,121:139-152.
APA He, Enyuan.,Zhao, Minghui.,Qiu, Xuelin.,Sibuet, Jean-Claude.,Wang, Jian.,...&Zhao, MH .(2016).Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance.JOURNAL OF ASIAN EARTH SCIENCES,121,139-152.
MLA He, Enyuan,et al."Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance".JOURNAL OF ASIAN EARTH SCIENCES 121(2016):139-152.
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