气候变化领域集成服务门户(CCPortal): Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build-Up

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DOI	10.1029/2020JB021331
	Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build-Up
	Noël C.; Passelègue F.X.; Violay M.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	Under upper crustal conditions, deformations are primarily brittle (i.e., localized) and accommodated by frictional mechanisms. At greater depth, deformations are ductile (i.e., distributed) and accommodated by crystal plasticity, diffusion mass transfer or cataclastic flow. The transition from the brittle to the ductile domain is not associated with a critical depth, but rather varies in time and space. One main parameter controlling the variation of this transition is the pore fluid pressure. On the one hand, a pore fluid pressure increase reduces the effective stresses and possibly increases the strain rate, bringing the system closer to brittle conditions. On the other hand, pore fluid can favor ductile mechanisms, mostly via chemical effects, by facilitating intra-crystalline plasticity, enhancing fluid-solid diffusion and fracture healing/sealing. We report triaxial laboratory experiments that investigated the effect of pore fluid pressure increase during the ductile deformation of Tavel limestone. Three injection rates were tested: 1, 5, and 10 MPa/min. We demonstrate that: (1) Under initially ductile conditions pore fluid pressure increase immediately turns the system from compaction to dilation. (2) Dilation is due to the development of localized shear fractures. However, the macroscopic localization of the deformation is not instantaneous when the ductile to brittle transition is surpassed; a transient creeping phase is first needed. (3) To reach macroscopic brittle failure of initially ductile samples, a critical dilatancy is required. (4) Injection rate controls the final fracture distribution. We demonstrate that pore pressure build-up in a rock undergoing ductile deformation can induce shear fracturing of the system. © 2021. American Geophysical Union. All Rights Reserved.
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/187270
作者单位	Laboratory of Experimental Rock Mechanics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
推荐引用方式 GB/T 7714	Noël C.,Passelègue F.X.,Violay M.. Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build-Up[J],2021,126(3).
APA	Noël C.,Passelègue F.X.,&Violay M..(2021).Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build-Up.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Noël C.,et al."Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build-Up".Journal of Geophysical Research: Solid Earth 126.3(2021).