A hypothesis is advanced that dynamic recrystallization of Earth materials undergoing solid state flow may represent a balance between grain size reduction and growth processes occurring directly in the boundary dislocation diffusion creep fields. Accordingly, recrystallized (D) stress (σ) at steady will be related by equation delineating field boundary, which general temperature dependent. Creep experiments on metallic rock analogue, Magnox, yielded D=10 1.12 exp[29.3/RT]σ −1.23...

Abstract We report ring shear experiments on simulated calcite fault gouges performed at fixed temperatures ( T ) within the range from 20°C to 600°C. The were wet, using pore fluid pressures P f of 10 ≤ 60 MPa. One series employed a constant effective normal stress 50 MPa, while in second series, was sequentially stepped 30 100 In all experiments, sliding velocity v 0.03 µm/s. results showed stable, velocity‐strengthening behavior 20°C, but weakening 100°C 550°C (for steps <3 µm/s),...

Research Article| August 01, 2013 Nanocrystalline slip zones in calcite fault gouge show intense crystallographic preferred orientation: Crystal plasticity at sub-seismic rates 18–150 °C Berend A. Verberne; Verberne * 1Department of Earth Sciences, Utrecht University, P.O. Box 80021, 3508 TA Utrecht, Netherlands *E-mail: B.A.Verberne@uu.nl. Search for other works by this author on: GSW Google Scholar Johannes H.P. de Bresser; Bresser André R. Niemeijer; Niemeijer Christopher J. Spiers;...

This paper reports uniaxial compaction creep experiments performed on porous calcite aggregates in the presence of CO 2 at controlled conditions similar to those relevant for geological storage carbonate reservoirs. The were conducted pre‐compacted various mean grain sizes range 1 250 μ m, under dry and wet conditions, temperatures 28–100°C applied effective stresses 4–40 MPa. Carbon dioxide was added samples pressures up 10 results demonstrate that granular shows virtually no creep, but...

Though the energy transition aims to phase out fossil fuels while continuing exploit subsurface for other storage solutions (e.g. geological CO2 storage, temporary hydrogen storage), natural gas, as a low-carbon carrier, will continue play role in our mix foreseeable future. In general, human activities change physical and chemical environment, which turn can lead surface subsidence induced seismicity. These phenomena may even after have stopped, observed gas extraction from giant Groningen...

Understanding the rheology of carbonates is crucial, as destructive earthquakes frequently occur in tectonically active carbonate regions (e.g., Corinth Rift Zone, Italian Apennines, and Sichuan Basin, China), leading to fatalities severe economic impacts. Seismic aseismic deformation can be understood terms frictional response, which based on underlying mechanisms. To grasp seismic potential faults carbonates, we studied conditions under dolomite fault gouge frictionally unstable, rate...

Abstract Induced earthquakes are occasionally associated with stress oscillations resulting from periodic industrial activities. Yet, the effects of on fault friction under realistic subsurface conditions not fully clear. We conducted normal experiments using simulated gouges derived major reservoirs and caprocks Changning shale gas field in situ conditions. Our experimental results reveal that most velocity‐strengthening quasi‐static loading. Interestingly, after applying oscillation, they...

In an attempt to resolve questions recently raised regarding the principal high‐temperature slip systems in calcite, optical quality single crystals have been uniaxially compressed at 300–800°C and a constant strain rate of ∼ 3×10 −5 s −1 . addition, cycling test was performed 650°C. The tests were all carried out with compression direction parallel , which lies ∼30° c axis makes angles 52° 23° poles two rhombohedral ( r ) planes. Axial strains 5–16% achieved tests. stress‐strain curves...

Major earthquakes frequently nucleate near the base of seismogenic zone, close to brittle-ductile transition. Fault zone rupture at greater depths is inhibited by ductile flow rock. However, microphysical mechanisms responsible for transition from brittle/frictional behaviour shallower remain unclear. Here we show that flow-to-friction in experimentally simulated calcite faults characterized a dislocation and diffusion creep dilatant deformation, involving incompletely accommodated grain...

Abstract. The ice microstructure in the lower part of North Greenland Eemian Ice Drilling (NEEM) core consists relatively fine-grained with a single maximum crystallographic preferred orientation (CPO) alternated by much coarser-grained partial (great circle) girdle or multi-maxima CPO. In this study, grain-size-sensitive (GSS) composite flow law Goldsby and Kohlstedt (2001) was used to study effects grain size premelting (liquid-like layer along boundaries) on strain rate NEEM core. results...

Previous laboratory experiments on coarse grained calcite materials at intermediate conditions of stress and temperature have shown low strain rate sensitivity flow stress, expressed by standard power law exponents n ≥ 7. This conflicts with conventional models for creep controlled dislocation climb ( = 3–4.5), a recovery mechanism widely used to explain steady‐state creep. paper addresses the question whether cross slip rather than is controlling conditions. New uniaxial compression tests...

Abstract Field studies of calcite mylonites often document microstructures produced by dislocation creep. In contrast, flow laws derived from experiments predict that rocks should deform mostly diffusion creep during tectonic processes. To investigate this apparent discrepancy, we compare stresses estimated microstructural piezometers to those obtained extrapolation experimentally laws. Considering shear zones different geological settings, a clear trend is observed increasing recrystallized...