Fluid-rock reaction weakening of fault zones

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August undefined, 2024

WebAug 1, 2014 · Fault rocks contain graphite veins and cement that locally constitute >50% of the rock. Individual graphite veins are as much as 1 cm wide, and are locally almost pure graphite, with minor muscovite and anatase. Hydrothermal graphite grain size (10–500 µm) is substantially greater than background metamorphosed organic matter (∼1 µm). WebJan 30, 2003 · The experiments presented here show that isostatic hydrothermal reaction of fault products formed in previously intact rock can result in significant strengthening of …

Fluid-rock reaction weakening of fault zones (1995) Robert P.

WebMetamorphic core complexes and associated detachment faults of the North American Cordillera represent gently dipping, normal-displacement shear zones (detachment zones) along which hot, deeper levels of the crust were transported upward and outward from underneath a brittlely distended upper plate. Structures that formed during the ductile-to … WebThe low permeabilities measured support models invoking high fluid pressure weakening of large faults with minimal fluid loss. The stability of structured water films with varying temperature, water pressure and water chemistry may produce a heterogeneous permeability profile with depth in fault zones. inch gage blocks

Fabric induced weakness of tectonic faults - Niemeijer - 2010 ...

WebFeb 1, 2004 · Several studies have focused on fluid-assisted reaction softening and fault weakening during the longterm evolution of fault zones (Caine et al., 1996; Holdsworth, 2004; Collettini et... WebJan 10, 2024 · A modified slip-weakening constitutive law is applied at contacts. We perform velocity-stepping experiments on both uniform and layered mixtures of quartz and talc analogs. We separately vary the proportion of talc in the uniform mixtures and talc layer thickness in the layered mixtures. WebMay 13, 2015 · Chemical reactions between the fluid and rock mass lead to erosion in the mineral particles and crystals, weakening of the particle bond strength, and changes in the mineral components... inch g9

Deformation processes and weakening mechanisms within the …

Fault zone fabric and fault weakness Nature

WebMay 13, 2015 · We determine the evolution of frictional strength, strain weakening behavior and permeability in fractures subject to dissolution and precipitation. We establish these relations through slide–hold–slide experiments, with hold times from 10 to 3000 s, on split limestone core, under hydraulically open and closed conditions. Fracture friction and … Webreaction weakening of fault zones In the absence of direct observations of high fluid pressure in active fault zones in crystalline rocks, the effects of fluids inahfcarmetWebDec 1, 2004 · Fluid‐rock reaction weakening of fault zones R. Wintsch, R. Christoffersen, A. Kronenberg Geology 1995 The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in meteoric water-dominated… Expand 402 View 2 excerpts, … inch full size

"WebJan 30, 2003 · The experimental results show how hydrothermal reactions in fault zones may lead to two competing, time-dependent effects; fault strengthening due to increased … " - Fluid-rock reaction weakening of fault zones

Fluid-rock reaction weakening of fault zones

WebAug 10, 2024 · Extensive fluid–rock reaction can produce layers of phyllosilicates, which can significantly weaken fault zones, as discussed below (e.g. Wintsch et al. 1995; Imber et al. 1997). A second difficulty in applying Byerlee's Law to the Earth relates to the composition of fault rocks. WebDec 1, 2005 · In both fault types, early cataclasis facilitates fluid influx into the active fault zone, leading to widespread alteration of the crushed material (reaction softening) and simultaneously...

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WebSep 24, 2024 · Nature Communications - Coupling between fault zone fluid flow, permeability evolution, and elastic stress transfer produces fault valving and fluid-driven …

WebJul 10, 1995 · Abstract. The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in meteoric water-dominated granitic fault systems, where mineral-aqueous fluid … WebDec 1, 2024 · The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in meteoric water-dominated granitic fault systems, where mineral-aqueous fluid equilibria predict that modal phyllosilicate will increase via feldspar replacement reactions. In …

WebDec 17, 2009 · Explanations for fault weakness include the presence of weak minerals, high fluid pressures within the fault core and dynamic processes such as normal stress reduction, acoustic fluidization or extreme weakening at high slip velocity. WebLarge normal fault zones are characterized by intense fracturing and hydrothermal alteration. Displacement is localized in a slip zone of cataclasite, breccia and phyllonite …

WebFluid-rock reaction weakening of fault zones. Wintsch, R. P. ; Christoffersen, R. ; Kronenberg, A. K. The presence of weak phyllosilicates may explain the low shear …

WebMay 15, 2000 · The Great Glen Fault Zone (GGFZ) is a major, reactivated strike‐slip fault within the lower Paleozoic Caledonian orogenic belt of the British Isles. The Late Devonian to Tertiary reactivation history… Expand 60 PDF Save Alert Low effective fault strength due to frictional-viscous flow in phyllonites, Karakoram Fault Zone, NW India inaheart guidelineWebabstract. The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in … inaheart.orgWebDec 17, 2009 · We show that fault weakening depends strongly on rock fabric and the distribution of weak phases within a fault zone. inch gallonWebNov 15, 2011 · Here, we show that fault zone structure has an important influence on mixed-mode fault slip behavior. Our field studies depict a complex fault zone structure where foliated horizons surround meter- to decameter-sized lenses of competent material. The foliated rocks are composed of weak mineral phases, possess low frictional … inahealthWebFeb 4, 2010 · The degree of weakening depends on the thickness of the weak layer. In nature, talc and most other weak minerals (clays and phyllosilicates) are formed by chemical and hydration reactions [ Imber et al., 1997; Jefferies et al., 2006; Schleicher et al., 2006; Collettini et al., 2009b ]. inch gamesWebApr 8, 2024 · Key Points At low temperature and pressure, chlorite is weak and velocity-strengthening and hornblende and epidote are strong and velocity-weakening Increasing chlorite content leads to mixtures becoming frictionally weaker and velocity-strengthening inaheatWebJan 30, 2003 · The experiments presented here show that isostatic hydrothermal reaction of fault products formed in previously intact rock can result in significant strengthening of fault zones. Strength recovery of our experimental fault zones was achieved by compaction of gouge material and healing of crack arrays that were formed during initial … inahead