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DOI	10.1016/j.epsl.2019.115967
	The role of metasomatic alteration on frictional properties of subduction thrusts: An example from a serpentinite body in the Franciscan Complex, California
	Hirauchi K.-I.; Yamamoto Y.; den Hartog S.A.M.; Niemeijer A.R.
发表日期	2020
ISSN	0012821X
卷号	531
英文摘要	Fluid–rock interaction within accretionary prisms drastically changes the frictional strength and slip stability of the fault zone. In order to understand the effect of ultramafic components on the degree of interplate coupling, we present data on frictional properties of a reaction zone between serpentinite and argillite in a tectonic mélange of the Franciscan Complex, central California. Field and petrographic observations indicate that the argillite and serpentinite along the lithological boundary are metasomatized to tremolite and talc schists, respectively, forming a ductile shear zone. Simulated gouges made from fault and wall rock samples collected are sheared at effective normal stresses (σneff) of 60–180 MPa and temperatures (T) of 20–400C∘, using a hydrothermal ring shear machine. The serpentinite is frictionally strong (steady-state friction coefficient μss=0.5–0.6), and exhibits both velocity-weakening and velocity-strengthening behavior. The μss of the argillite and tremolite schist increases up to 0.7 and 0.6, respectively, with increasing σneff and T, while (a−b) transitions from positive to negative with increasing T. At a given experimental condition, μ and (a−b) values are lower and higher for the tremolite schist than for the argillite. In contrast, the talc schist exhibits very low friction (μss=0.1–0.2) and velocity-strengthening behavior at all experimental conditions tested. Our results demonstrate that Si-metasomatism along the argillite–serpentinite contact results in reduced friction and stabilized slip, forming frictionally weak, velocity-strengthening regions in the megathrust zone. © 2019 Elsevier B.V.
关键词	Franciscan Complex friction interplate coupling metasomatism serpentinite
英文关键词	Lithology; Magnesite; Mineralogy; Slip forming; Talc; Velocity; Effective normal stress; Experimental conditions; Franciscan Complex; Frictional properties; Interplate coupling; Metasomatic alterations; metasomatism; Serpentinite; Friction; accretionary prism; friction; intraplate process; metasomatism; serpentinite; silicon; subduction; thrust fault; California; United States
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/202649
作者单位	Department of Geosciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan; Department of Mathematical Science and Advanced Technology, Japan Agency for Marine-Earth Science and Technology, Showa-machi 3173-25, Kanazawa-ku, Yokohama, 236-0001, Japan; The Lyell Centre, Heriot-Watt University, Research Avenue South, Edinburgh, EH14 4AP, United Kingdom; Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
推荐引用方式 GB/T 7714	Hirauchi K.-I.,Yamamoto Y.,den Hartog S.A.M.,et al. The role of metasomatic alteration on frictional properties of subduction thrusts: An example from a serpentinite body in the Franciscan Complex, California[J],2020,531.
APA	Hirauchi K.-I.,Yamamoto Y.,den Hartog S.A.M.,&Niemeijer A.R..(2020).The role of metasomatic alteration on frictional properties of subduction thrusts: An example from a serpentinite body in the Franciscan Complex, California.Earth and Planetary Science Letters,531.
MLA	Hirauchi K.-I.,et al."The role of metasomatic alteration on frictional properties of subduction thrusts: An example from a serpentinite body in the Franciscan Complex, California".Earth and Planetary Science Letters 531(2020).