气候变化领域集成服务门户(CCPortal): Fluid Infiltration Through Oceanic Lower Crust in Response to Reaction-Induced Fracturing: Insights From Serpentinized Troctolite and Numerical Models

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DOI	10.1029/2020JB020268
	Fluid Infiltration Through Oceanic Lower Crust in Response to Reaction-Induced Fracturing: Insights From Serpentinized Troctolite and Numerical Models
	Yoshida K.; Okamoto A.; Shimizu H.; Oyanagi R.; Tsuchiya N.; Oman Drilling Project Phase 2 Science Party
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	The mechanisms of fluid penetration through the gabbroic lower crust are important for the hydration of oceanic lithosphere. In the Oman ophiolite, which preserves an entire sequence of oceanic lithosphere formed at a fast-spreading ridge, the layered gabbros and dunites are extensively serpentinized. In this paper, we describe the characteristic textures of serpentinized troctolite and olivine gabbros recovered from the CM1A site of the Oman Drilling Project. In the troctolite, an olivine mesh texture is pervasively developed and is characterized by two types of veins: early lizardite + brucite + magnetite and late Al-rich lizardite + magnetite. These veins suggest the initiation of serpentinization at <350°C and a supply of Si and Al from plagioclase during the later stages of serpentinization. Plagioclase surrounding serpentinized olivine grains commonly shows radial fracturing. Numerical simulations using the discrete element method applied to coupled fluid flow, reaction, and fracturing reveal that volume expansion of olivine grains during serpentinization results in the simultaneous fracturing of olivine and surrounding plagioclase, and that the thermal stress during cooling of oceanic lithosphere might also cause preferential olivine fracturing prior to serpentinization. The simulations also predict a self-organizing fracture network that connects the olivine grains and passes through both olivine-rich and olivine-poor layers, resulting in permeability enhancement during serpentinization. Our results suggest that reaction-induced fracturing plays an essential role in the infiltration of seawater through the lower crust and into the mantle within oceanic lithosphere. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	alteration and weathering processes; discrete element method; hydrothermal system; mid-ocean ridge processes; oceanic crust
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187486
作者单位	Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, Sendai, Japan; Geotechnical Analysis Group, Advanced Analysis Department, Civil Engineering Design Division, Kajima Corporation, Japan, Tokyo, Japan; Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
推荐引用方式 GB/T 7714	Yoshida K.,Okamoto A.,Shimizu H.,et al. Fluid Infiltration Through Oceanic Lower Crust in Response to Reaction-Induced Fracturing: Insights From Serpentinized Troctolite and Numerical Models[J],2020,125(11).
APA	Yoshida K.,Okamoto A.,Shimizu H.,Oyanagi R.,Tsuchiya N.,&Oman Drilling Project Phase 2 Science Party.(2020).Fluid Infiltration Through Oceanic Lower Crust in Response to Reaction-Induced Fracturing: Insights From Serpentinized Troctolite and Numerical Models.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Yoshida K.,et al."Fluid Infiltration Through Oceanic Lower Crust in Response to Reaction-Induced Fracturing: Insights From Serpentinized Troctolite and Numerical Models".Journal of Geophysical Research: Solid Earth 125.11(2020).