气候变化领域集成服务门户(CCPortal): Fluid overpressure in subduction plate boundary caused by mantle-derived fluids

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DOI	10.1016/j.epsl.2020.116199
	Fluid overpressure in subduction plate boundary caused by mantle-derived fluids
	Nishiyama N.; Sumino H.; Ujiie K.
发表日期	2020
ISSN	0012821X
卷号	538
英文摘要	Subduction plate boundaries are commonly weak owing to fluid overpressure. The generation of fluid overpressure has been invoked for compaction disequilibrium and mineral dehydration in subducting sediments and altered oceanic crust. The subduction mélange in the Shimanto accretionary complex, southwest Japan, preserves the quartz-calcite-filled shear veins and sigmoidal extension veins formed under fluid overpressure near the downdip limit of the thermally-controlled seismogenic zone. The shear veins record the repeated low-angle brittle thrusting under fluid overpressure, while the extension veins constitute the Riedel shear zones developed during subduction under vertical maximum principle stress. To examine the origin of overpressured fluids, we conducted fluid inclusion and noble gas analyses on the shear and extension veins. The result of fluid inclusion analysis shows various fluid pressures between lithostatic to hydrostatic pressures during the vein formation, which were associated with warm fluid infiltration. 3He/4He values of shear veins and extension veins range 1.6–2.5 Ra and 1.6–2.3 Ra, respectively, indicating the presence of mantle helium. 40Ar/36Ar values and 84Kr/36Ar and 130Xe/36Ar ratios of the veins are similar to those of serpentinized mantle, suggesting that mantle helium originated from serpentinized mantle. Because the mantle-derived rocks such as peridotite and serpentinite are absent in the mélange, the results of noble gas analyses represent the infiltration of fluids from the serpentinized mantle into the mélange shear zone. Our results show that an infiltration of fluids derived from serpentinized mantle contributed the fluid overpressure in the mélange shear zone near the downdip limit of the seismogenic zone. © 2020 Elsevier B.V.
关键词	crack-seal veins fluid flow fluid inclusions fluid overpressure mantle helium noble gas
英文关键词	Calcite; Helium; Hydrostatic pressure; Inert gases; Magnesite; Metamorphic rocks; Mineralogy; Seismographs; Accretionary complex; Altered oceanic crusts; Fluid inclusion; Fluid overpressure; Fluid pressures; Mantle heliums; Plate boundaries; Seismogenic zones; Flow of fluids; fluid flow; fluid inclusion; helium; mantle structure; noble gas; overpressure; plate boundary; plate motion; plate tectonics
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202809
作者单位	Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan; Graduate School of Arts and Sciences, The University of Tokyo, Japan
推荐引用方式 GB/T 7714	Nishiyama N.,Sumino H.,Ujiie K.. Fluid overpressure in subduction plate boundary caused by mantle-derived fluids[J],2020,538.
APA	Nishiyama N.,Sumino H.,&Ujiie K..(2020).Fluid overpressure in subduction plate boundary caused by mantle-derived fluids.Earth and Planetary Science Letters,538.
MLA	Nishiyama N.,et al."Fluid overpressure in subduction plate boundary caused by mantle-derived fluids".Earth and Planetary Science Letters 538(2020).