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Deep Seismic Structure Across the Southernmost Mariana Trench: Implications for Arc Rifting and Plate Hydration
Wan, Kuiyuan; Lin, Jian1; Xia, Shaohong; Sun, Jinlong; Xu, Min; Yang, Hongfeng2; Zhou, Zhiyuan; Zeng, Xin; Cao, Jinghe; Xu, Huilong
2019
Source PublicationJOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
ISSN2169-9313
Volume124Issue:5Pages:4710
AbstractThe southernmost Mariana margin lacks a mature island arc and thus differs significantly from the central-north Mariana and Izu-Bonin margins. This paper presents a new P wave velocity model of the crust and uppermost mantle structure based on a 349-km-long profile of wide-angle reflection/refraction data. The active source seismic experiment was conducted from the subducting Pacific plate to the overriding Philippine plate, passing through the Challenger Deep. The subducting plate has an average crustal thickness of similar to 6.0 km with Vp of 7.0 +/- 0.2 km/s at the base of the crust and low values of only 5.5-6.9 km/s near the trench axis. The uppermost mantle of the subducting plate is characterized by low velocities of 7.0-7.3 km/s. The overriding plate has a maximum crustal thickness of similar to 18 km beneath the forearc with Vp of similar to 7.4 km/s at the crustal bottom and 7.5-7.8 km/s in the uppermost mantle. A zone of slight velocity reduction is imaged beneath the Southwest Mariana Rift that is undergoing active rifting. The observed significant velocity reduction in a near-trench crustal zone of similar to 20-30 km in the subducting plate is interpreted as a result of faulting-induced porosity changes and fracture-filling fluids. The velocity reduction in the uppermost mantle of both subducting and overriding plates is interpreted as mantle serpentinization with fluid sources from dehydration of the subducting plate and/or fluid penetration along faults. Plain Language Summary The southernmost Mariana margin is a convergence margin that lacks a mature island arc. The trench reaches the deepest point on Earth at the Challenger Deep, the origin of which is still little known. We acquired and analyzed new active source wide-angle reflection/refraction seismic data along a profile across the Challenge Deep, obtaining a new model of crustal and uppermost mantle velocity structure of both the subducting Pacific and overriding Philippine Sea plates. Significant velocity reduction is observed in the crust of the subducting plate, especially in a 20- to 30-km-wide zone near the trench axis, which is interpreted as a result of faulting-induced porosity changes and fracture-filling fluids. A zone of slight velocity reduction is imaged beneath the tectonically active Southwest Mariana Rift. Significant velocity reduction is also observed in the uppermost mantle of both subducting and overriding plates and is interpreted as a result of mantle serpentinization.
DepartmentOMG
Keywordarc rifting plate hydration southernmost Mariana Trench seismic tomography
DOI10.1029/2018JB017080
Citation statistics
Cited Times:1[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.scsio.ac.cn/handle/344004/17959
Collection中科院边缘海地质重点实验室
Affiliation1.Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Ocean & Marginal Sea Geol, Guangzhou, Guangdong, Peoples R China
2.Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA
3.Chinese Univ Hong Kong, Fac Sci, Earth Syst Sci Programme, Shatin, Hong Kong, Peoples R China
Recommended Citation
GB/T 7714		 Wan, Kuiyuan,Lin, Jian,Xia, Shaohong,et al. Deep Seismic Structure Across the Southernmost Mariana Trench: Implications for Arc Rifting and Plate Hydration[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2019,124(5):4710, 4727.
APA Wan, Kuiyuan.,Lin, Jian.,Xia, Shaohong.,Sun, Jinlong.,Xu, Min.,...&Xu, Huilong.(2019).Deep Seismic Structure Across the Southernmost Mariana Trench: Implications for Arc Rifting and Plate Hydration.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,124(5),4710.
MLA Wan, Kuiyuan,et al."Deep Seismic Structure Across the Southernmost Mariana Trench: Implications for Arc Rifting and Plate Hydration".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 124.5(2019):4710.
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