DOI: 10.1016/j.tecto.2021.228811
论文题名: The role of shale content and pore-water saturation on frictional properties of simulated carbonate faults
作者: Ruggieri R. ; Scuderi M.M. ; Trippetta F. ; Tinti E. ; Brignoli M. ; Mantica S. ; Petroselli S. ; Osculati L. ; Volontè G. ; Collettini C.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 807 语种: 英语
中文关键词: 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170894
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Tectonophysics,2021-01-01,807