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DOI	10.1016/j.tecto.2021.228811
	The role of shale content and pore-water saturation on frictional properties of simulated carbonate faults
	Ruggieri R.; Scuderi M.M.; Trippetta F.; Tinti E.; Brignoli M.; Mantica S.; Petroselli S.; Osculati L.; Volontè G.; Collettini C.
发表日期	2021
ISSN	00401951
卷号	807
英文摘要	The presence of weak phyllosilicates in mature carbonate fault zones has been invoked to explain weak faults. However, the relation between frictional strength, fault stability, mineralogical composition, and fabric of fault gouge, composed of strong and weak minerals, is poorly constrained. We used a biaxial apparatus to systematically shear different mixtures of shale (68% clay, 23% quartz and 4% plagioclase) and calcite, as powdered gouge, at room temperature, under constant normal stresses of 30, 50, 100 MPa and under room-dry and pore fluid-saturated conditions, i.e. CaCO3-equilibrated water. We performed 30 friction experiments during which velocity-stepping and slide-hold-slide tests were employed to assess frictional stability and to measure frictional healing, respectively. Our frictional data indicate that the mineralogical composition of fault gouges significantly affects frictional strength, stability, and healing as well as the presence of CaCO3-equilibrated water. Under room-dry condition, the increasing shale content determines a reduction in frictional strength, from μ = 0.71 to μ = 0.43, a lowering of the healing rates and a transition from velocity-weakening to velocity-strengthening behavior. Under wet condition, with increasing shale content we observe a more significant reduction in frictional strength (μ = 0.65–0.37), a near-zero healing and a velocity strengthening behavior. Microstructural investigations evidence a transition from localized deformation promoted by grain size reduction, in calcite-rich samples, to a more distributed deformation with frictional sliding along clay-enriched shear planes in samples with shale content greater than 50%. For faults cutting across sedimentary sequences composed of carbonates and clay-rich sediments, our results suggest that clay concentration and its ability to form foliated and interconnected networks promotes important heterogeneities in fault strength and slip behavior. © 2021 Elsevier B.V.
关键词	Carbonate faults Clay Fault slip behavior Friction
英文关键词	Calcite; Calcium carbonate; Carbonate minerals; Deformation; Feldspar; Friction; Silicates; Velocity; Distributed deformation; Friction experiments; Frictional properties; Grain-size reduction; Interconnected network; Localized deformations; Microstructural investigation; Mineralogical compositions; Shale; carbonate rock; clay soil; fault gouge; fault zone; numerical model; pore pressure; porewater; shale; source rock; structural geology
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/208061
作者单位	Department of Earth Sciences, University of Rome La Sapienza, Rome, 00185, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Rome, 00143, Italy; Reservoir & Petroleum Engineering Dpt, Eni SpA, San Donato Mianese, 20097, Italy; Upstream R&D Dpt., Eni SpA, San Donato Mianese, 20097, Italy
推荐引用方式 GB/T 7714	Ruggieri R.,Scuderi M.M.,Trippetta F.,et al. The role of shale content and pore-water saturation on frictional properties of simulated carbonate faults[J],2021,807.
APA	Ruggieri R..,Scuderi M.M..,Trippetta F..,Tinti E..,Brignoli M..,...&Collettini C..(2021).The role of shale content and pore-water saturation on frictional properties of simulated carbonate faults.Tectonophysics,807.
MLA	Ruggieri R.,et al."The role of shale content and pore-water saturation on frictional properties of simulated carbonate faults".Tectonophysics 807(2021).