气候变化领域集成服务门户(CCPortal): Deep fluid release in warm subduction zones from a breached slab seal

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DOI	10.1016/j.epsl.2019.116046
	Deep fluid release in warm subduction zones from a breached slab seal
	Smit M.A.; Pogge von Strandmann P.A.E.
发表日期	2020
ISSN	0012821X
卷号	534
英文摘要	Petrological models and seismic data from subduction zones with geotherms of 7 K km−1 or higher suggest that slabs in these systems dehydrate effectively in the forearc. A large fluid flux is nevertheless released from these slabs at and beyond subarc depth, suggesting that large amounts of H2O can remain slab-bound to much greater depth than expected. We propose that this is due to a transient sealing effect exerted by the subducting lower crust. To test this concept, the petrological and geochemical evolution of such gabbroic crust is investigated through a textural, petrological and Li-chronometric analysis of eclogitized gabbros from an exhumed ultrahigh-pressure terrane. The samples record pristine transitions from dry, rigid gabbro to hydrated eclogite and eclogite mylonite, which occurred when these rocks resided at 90-110 km depth. The observations characterize step-by-step the deformation and overstepped mineral reactions that following the influx of external fluids along a developing network of permeable shear zones. Lithium chronometry indicates that the gabbroic rocks were breached and permeated within a few weeks at a very specific depth within the 90-110 km interval—depths where, in warm subduction zones, large fluid-filled channel system emanate from the slab. The data support a model in which fluids produced in the deserpentinizing slab mantle are trapped at high pore pressure beneath the slab Moho and are ultimately released at subarc depth where the lower crust fails and develops highly permeable fluid vents. The subducting lower crust thus may play an important role in regulating H2O and element budgets, and controlling slab rheology in warm subduction zones. © 2019 Elsevier B.V.
关键词	arc magmatism earthquakes eclogite gabbro-to-eclogite transition warm subduction zones
英文关键词	Budget control; Earthquakes; Gasoline; Petrology; Seismology; Arc magmatism; Channel systems; Eclogites; Gabbroic rocks; Geochemical evolution; Mineral reactions; Subduction zones; Ultrahigh pressure; Metamorphic rocks; earthquake; eclogite; gabbro; igneous geochemistry; magmatism; petrology; seismic data; slab; subduction zone; terrane; texture
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/202893
作者单位	Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver, V6T 1Z4, Canada; Institute of Earth and Planetary Sciences, University College London and Birkbeck, Gower Street, London, WC1E 6BT, United Kingdom
推荐引用方式 GB/T 7714	Smit M.A.,Pogge von Strandmann P.A.E.. Deep fluid release in warm subduction zones from a breached slab seal[J],2020,534.
APA	Smit M.A.,&Pogge von Strandmann P.A.E..(2020).Deep fluid release in warm subduction zones from a breached slab seal.Earth and Planetary Science Letters,534.
MLA	Smit M.A.,et al."Deep fluid release in warm subduction zones from a breached slab seal".Earth and Planetary Science Letters 534(2020).