The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
Francois Renard - One of the best experts on this subject based on the ideXlab platform.
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The role of Pressure Solution creep in the ductility of the earth's upper crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth's upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modelling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behaviour of fault and shear zones. The conclusions discuss recent advances for modelling Pressure Solution creep and the main questions that remain to be solved.
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The Role of Pressure Solution Creep in the Ductility of the Earth’s Upper Crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:Abstract The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth’s upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions, or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modeling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behavior of fault and shear zones. The conclusions discuss recent advances for modeling Pressure Solution creep and the main questions that remain to be solved.
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Experimental calcite disSolution under stress: Evolution of grain contact microstructure during Pressure Solution creep
Journal of Geophysical Research, 2010Co-Authors: Delphine Croizé, Francois Renard, Knut Bjørlykke, Dag Kristian DystheAbstract:[1] For the first time, nanometer reSolution techniques both in situ and ex situ were compared in order to study calcite disSolution under stress. The obtained results enabled identification of the relative importance of Pressure Solution driven by normal load and free surface disSolution driven by strain energy. It is found that Pressure Solution of calcite crystals at the grain scale occurred by two different mechanisms. Diffusion of the dissolved solid took place either at a rough calcite/indenter interface, or through cracks that propagated from the contact toward the less stressed part of the crystal. It is also found that strain rates are mostly a function of the active process, i.e., Pressure Solution associated or not with cracks, rather than being influenced by stress variations. Strain rates obtained in this study are in agreement with published data of experimental calcite and carbonate disSolution under stress.
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Single-contact Pressure Solution creep on calcite monocrystals
arXiv: Geophysics, 2008Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, V. TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40 degrees C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
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Single-contact Pressure Solution creep on calcite monocrystals
2005Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, Vladimir TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40°C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
Jean-pierre Gratier - One of the best experts on this subject based on the ideXlab platform.
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The role of Pressure Solution creep in the ductility of the earth's upper crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth's upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modelling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behaviour of fault and shear zones. The conclusions discuss recent advances for modelling Pressure Solution creep and the main questions that remain to be solved.
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The Role of Pressure Solution Creep in the Ductility of the Earth’s Upper Crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:Abstract The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth’s upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions, or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modeling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behavior of fault and shear zones. The conclusions discuss recent advances for modeling Pressure Solution creep and the main questions that remain to be solved.
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Single-contact Pressure Solution creep on calcite monocrystals
arXiv: Geophysics, 2008Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, V. TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40 degrees C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
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Single-contact Pressure Solution creep on calcite monocrystals
2005Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, Vladimir TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40°C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
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Experimental Pressure Solution compaction of synthetic halite/calcite aggregates
Tectonophysics, 2004Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Robert Guiguet, Francois Renard, Dag Kristian Dysthe, Vladimir TraskineAbstract:Experimental observations are reported of weakening of sediment-like aggregates by addition of hard particles. Sieved mixtures of calcite and halite grains are experimentally compacted in drained Pressure cells in the presence of a saturated aqueous Solution. The individual halite grains deform easily by Pressure Solution creep whereas calcite grains act as hard objects and resist compaction. The fastest rate of compaction of the mixed aggregate is not obtained for a 100% halite aggregate but for a content of halite grains between 45% and 75%. We propose that this unusual compaction behavior reflects the competition between two mechanisms at the grain scale: intergranular Pressure Solution at grain contacts and grain boundary healing between halite grains that prevent further compaction.
Dag Kristian Dysthe - One of the best experts on this subject based on the ideXlab platform.
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The role of Pressure Solution creep in the ductility of the earth's upper crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth's upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modelling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behaviour of fault and shear zones. The conclusions discuss recent advances for modelling Pressure Solution creep and the main questions that remain to be solved.
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The Role of Pressure Solution Creep in the Ductility of the Earth’s Upper Crust
Advances in Geophysics, 2013Co-Authors: Jean-pierre Gratier, Dag Kristian Dysthe, Francois RenardAbstract:Abstract The aim of this review is to characterize the role of Pressure Solution creep in the ductility of the Earth’s upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure Solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (mainly the presence of phyllosilicates minerals that activate Pressure Solution) and on its interaction with fracturing and healing processes (that activate and slow down Pressure Solution, respectively). The present review combines three approaches: natural observations, theoretical developments, and laboratory experiments. Natural observations can be used to identify the Pressure Solution markers necessary to evaluate creep law parameters, such as the nature of the material, the temperature and stress conditions, or the geometry of mass transfer domains. Theoretical developments help to investigate the thermodynamics and kinetics of the processes and to build theoretical creep laws. Laboratory experiments are implemented in order to test the models and to measure creep law parameters such as driving forces and kinetic coefficients. Finally, applications are discussed for the modeling of sedimentary basin compaction and fault creep. The sensitivity of the models to time is given particular attention: viscous versus plastic rheology during sediment compaction; steady state versus non-steady state behavior of fault and shear zones. The conclusions discuss recent advances for modeling Pressure Solution creep and the main questions that remain to be solved.
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Experimental calcite disSolution under stress: Evolution of grain contact microstructure during Pressure Solution creep
Journal of Geophysical Research, 2010Co-Authors: Delphine Croizé, Francois Renard, Knut Bjørlykke, Dag Kristian DystheAbstract:[1] For the first time, nanometer reSolution techniques both in situ and ex situ were compared in order to study calcite disSolution under stress. The obtained results enabled identification of the relative importance of Pressure Solution driven by normal load and free surface disSolution driven by strain energy. It is found that Pressure Solution of calcite crystals at the grain scale occurred by two different mechanisms. Diffusion of the dissolved solid took place either at a rough calcite/indenter interface, or through cracks that propagated from the contact toward the less stressed part of the crystal. It is also found that strain rates are mostly a function of the active process, i.e., Pressure Solution associated or not with cracks, rather than being influenced by stress variations. Strain rates obtained in this study are in agreement with published data of experimental calcite and carbonate disSolution under stress.
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Single-contact Pressure Solution creep on calcite monocrystals
arXiv: Geophysics, 2008Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, V. TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40 degrees C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
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Single-contact Pressure Solution creep on calcite monocrystals
2005Co-Authors: Sergey Zubtsov, Jean-pierre Gratier, Francois Renard, Dag Kristian Dysthe, Vladimir TraskineAbstract:Pressure Solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40°C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated Solution of calcite and in a calcite-saturated aqueous Solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous Solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous Solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this Solution. In contrast, the experiments conducted in a calcite-saturated aqueous Solution show moderate indentation rate and the dry control experiments did not show any measurable deformation. The rate of calcite indentation is found to be inversely proportional to the indenter diameter, thus indicating that the process is diffusion-controlled. The microcracks in the disSolution region under the indenter dramatically enhance the rate of calcite indentation by a significant reduction of the distance of solute transport in the trapped fluid phase. This result indicates that care should be taken in extrapolating the kinetic data of Pressure Solution creep from one mineral to another.
Christopher J. Spiers - One of the best experts on this subject based on the ideXlab platform.
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compaction creep of simulated anhydrite fault gouge by Pressure Solution theory v experiments and implications for fault sealing
Geological Society London Special Publications, 2015Co-Authors: Anne Pluymakers, Christopher J. SpiersAbstract:The sealing and healing behaviour of faults filled with anhydrite gouge, by processes such as Pressure Solution, is of interest in relation both to the integrity of faults cutting geological storage systems sealed by anhydrite caprocks and to seismic events that may nucleate in anhydrite-bearing sequences, such as those present in the seismogenic zone beneath the Apennines. We have developed a detailed series of kinetic models for Pressure Solution in anhydrite fault gouge, allowing for disSolution, diffusion and precipitation control, to estimate the time scale on which such sealing and healing effects occur. We compare the models obtained with previously reported experimental data on compaction creep rates in simulated anhydrite fault gouge, tested under wet, upper crustal conditions. The results confirm earlier indications that compaction under these conditions likely occurs by diffusion-controlled Pressure Solution. Applying our most rigorous model for diffusion-controlled Pressure Solution, constrained by the fit to the experimental data, we infer that anhydrite fault sealing will occur in a few decades at most, which is rapid compared with both CO2 storage time scales and with the recurrence interval for seismicity in the Apennines.
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Kinetic effects of microscale plasticity at grain boundaries during Pressure Solution
Journal of Geophysical Research, 2009Co-Authors: Reinier Van Noort, Christopher J. SpiersAbstract:[1] It is generally assumed in kinetic models for Pressure Solution in materials such as quartz that the effective disSolution rate coefficient in grain boundaries is equal to the conventional geochemical disSolution rate coefficient on a free surface. However, predictions based on this assumption usually overestimate both natural and experimental Pressure Solution rates even when evidence for disSolution rate control is strong. A possible explanation for this discrepancy is that grain boundary structure and dissipative processes such as microscale plasticity in the grain boundary can decrease this effective rate coefficient. On the basis of a simple grain boundary model assuming an island-channel structure, we have derived a preliminary model for the effect that dissipation by plastic deformation (work-hardening flow and creep) of grain boundary islands has on disSolution-controlled Pressure Solution rates. Comparing the predictions of this model with the experimental data on quartz Pressure Solution rates, we see that microscale plasticity at grain boundary islands does slow down Pressure Solution and can help explain the discrepancies between observed and theoretical Pressure Solution rates. When applied to Pressure Solution creep of sandstones or fault rocks in nature, our model predicts that grain boundary plastic deformation in quartz might have a significant effect at depths beyond ∼9–10 km.
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Influence of grain boundary structure on disSolution controlled Pressure Solution and retarding effects of grain boundary healing
Journal of Geophysical Research, 2008Co-Authors: Reinier Van Noort, Hendrica J. M. Visser, Christopher J. SpiersAbstract:[1] It is widely accepted that the structure of a grain boundary undergoing Pressure Solution can have a strong influence on the rates at which diffusive transport in the grain boundary occurs. However, the influence of grain boundary structure on internal grain boundary disSolution rates has received little attention, despite evidence that disSolution controlled Pressure Solution in quartz is slower than expected assuming disSolution kinetics appropriate for free surfaces. In this paper, three hypothetical steady state grain boundary structures are defined and the influence of these structures on disSolution controlled Pressure Solution rates in an elastic solid are considered by deriving simple models based on internal grain boundary mass and energy balances. It is found that average disSolution rates in a rough grain boundary (island-channel network) are slowed down by up to 13% compared to disSolution in a flat grain boundary containing a thin fluid film. This can only partly account for the discrepancy between models and experiments reported in the literature. In addition a model is derived providing a criterion or “yield stress” for Pressure Solution, below which the process is prevented by surface energy driven grain boundary healing (progressive reduction of the contact area filled by connected fluid). This “yield stress criterion” for Pressure Solution offers a further explanation for reduced rates or cessation of Pressure Solution at low effective stresses in nature and experiment. Using this criterion, limiting porosity depth curves are predicted for sandstones compacting by Pressure Solution, which show favorable agreement with porosity-depth data for quartz sandstones.
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Effects of orientation on the diffusive properties of fluid-filled grain boundaries during Pressure Solution
Physics and Chemistry of Minerals, 2006Co-Authors: R. Van Noort, Christopher J. Spiers, Colin J. PeachAbstract:An unresolved issue in the study of Pressure Solution in rock materials is the dependence of grain boundary structure and diffusive properties on the mutual orientation of neighbouring grain lattices. We report electrical measurements yielding the diffusivity of differently oriented halite–glass and halite–halite contacts loaded in the presence of brine. The halite–glass contact experiments show Pressure Solution of the halite and an effect of halite lattice orientation on grain boundary transport. Post-mortem observations show an orientation-dependent grain boundary texture controlled by the periodic bond chains in the halite structure. It is inferred that this texture determines the internal grain boundary structure and properties during Pressure Solution. In the halite–halite experiments neck-growth occurred, its rate depending on twist-misorientation. The results imply that deformation by Pressure Solution may lead to lattice-preferred orientation development, and that polymineralic rocks may deform faster at lower stresses than monomineralic rocks.
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Diffusive properties of fluid-filled grain boundaries measured electrically during active Pressure Solution
Earth and Planetary Science Letters, 2002Co-Authors: Siese De Meer, Christopher J. Spiers, Colin J. Peach, Tohru WatanabeAbstract:Abstract Diffusion through ‘wetted’ grain boundaries is often the rate limiting process during rock deformation by intergranular Pressure Solution. However, the underlying processes operative within such boundaries are poorly understood. In this contribution we have studied the diffusive properties of wetted grain boundaries by measuring the electrical resistivity of single, annular halite–glass contacts undergoing active Pressure Solution. Optical observation shows continuous growth (i.e. widening) of the annular contacts by Pressure Solution. From the resistivity measurements and making use of the Nernst–Einstein equation, it was possible to calculate the apparent grain boundary diffusion coefficient Z=DδC (i.e. the product of grain boundary diffusion coefficient D, grain boundary film thickness δ and the solubility C of the diffusing species in the grain boundary fluid) during the Pressure Solution process. The Z-values obtained lie in the range 3×10−20–2×10−18 m3/s, show an inverse dependence on normal stress (σn) and agree well with values inferred previously from single contact and polycrystalline compaction experiments.
Bjørn Jamtveit - One of the best experts on this subject based on the ideXlab platform.
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High-reSolution measurements of Pressure Solution creep.
Physical Review E, 2003Co-Authors: Dag Kristian Dysthe, Francois Renard, Jens Feder, Bjørn Jamtveit, Paul Meakin, Torstein JøssangAbstract:Two dilatometers with high precision and stability have been developed for measurement of indentation by Pressure Solution creep. The indentation of gold wires or glass cylinders into sodium chloride has been measured with down to 10 A accuracy and 6% precision. The indentation curves show a strong history dependence and the indentation rate decreases by three orders of magnitude over 400 h. The indentation mechanism is shown to be a Pressure Solution creep process in which material is dissolved at the indentor-sodium chloride contacts and transported to the free surface, where it precipitates in the proximity of the indentors. The indentation rates are not controlled by precipitation rates, the density of preexisting dislocations in the material, by change in the contact widths, or by ordinary plastic deformation. Small amplitude sinusoidal variations of temperature and normal stress are shown to have a large effect on the indentation rate. Moreover, sudden increase in normal stress from the indentor on the sodium chloride is shown to initiate an increased, time-dependent indentation rate. A model for Pressure Solution creep with time-dependent contact sizes explains the history dependence of the indentation data presented.
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Coupling between Pressure Solution creep and diffusive mass transport in porous rocks
Journal of Geophysical Research: Solid Earth, 2002Co-Authors: Elisabeth Gundersen, Francois Renard, Dag Kristian Dysthe, Knut Bjørlykke, Bjørn JamtveitAbstract:Received 29 September 2000; revised 25 January 2002; accepted 30 January 2002; published XX Month 2002. [1] Pressure Solution is widely regarded as a mechanism of ductile deformation in the upper crust. It is driven by stress differences and its rate is affected by temperature, grain size, and fluid chemistry. Pressure Solution involves disSolution at grain contacts under high stress and precipitation at grain contacts on pore surfaces under low stress, leading to porosity reduction by precipitation in the pore space or by grain indentation. For a system closed at a grain scale, Pressure Solution is traditionally described by a mechanism involving three steps: (1) disSolution at intergranular interfaces, (2) diffusion of solutes inside the contact between two grains, and (3) precipitation on the surface of the grains in contact with the pore fluid. In this paper we propose a model where we have added a fourth step to this process, diffusive transport to other open pores, to account for the macroscopic diffusion of solutes in pore fluids, such that the deformation is not closed at the grain scale. In this model, differences in mineral solubility due to variations in stress and grain size produce concentration gradients which drive diffusive mass transport. The interaction between Pressure Solution at a grain scale and transport over distances of several grains can lead to the amplification of initial porosity heterogeneities and subsequent localization of deformation. Regions of intense disSolution compact and form ‘‘bands’’ in close proximity to regions where the porosity reduction is mainly due to cementation. Pressure Solution augmented by large-scale diffusional transport will cause mass transport from fine-grained to coarse-grained rock volumes. We show that such processes are important during both diagenesis of sediments and compaction of fault gouge. INDEX TERMS: 3902 Mineral Physics: Creep and deformation; 5114 Physical Properties of Rocks: Permeability and porosity; 8045 Structural Geology: Role of fluids; 8159 Tectonophysics: Evolution of the Earth: Rheology—crust and lithosphere; KEYWORDS: cementation, compaction, diagenesis, gouge, Pressure Solution, transport Citation: Gundersen, E., F. Renard, D. K. Dysthe, K. Bjorlykke, and B. Jamtveit, Coupling between Pressure Solution creep and diffusive mass transport in porous rocks, J. Geophys. Res., 107(0), XXXX, doi:10.1029/2001JB000287, 2002.
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Enhanced Pressure Solution creep rates induced by clay particles: Experimental evidence in salt aggregates
Geophysical Research Letters, 2001Co-Authors: Francois Renard, Dag Kristian Dysthe, Jens Feder, Knut Bjørlykke, Bjørn JamtveitAbstract:Pressure Solution is responsible for mechano-chemical compaction of sediments in the upper crust (2–10 km). This process also controls porosity variations in a fault gouge after an earthquake. We present experimental results from chemical compaction of aggregates of halite mixed with clays. It is shown that clay particles (1–5 microns) greatly enhance the deformation by Pressure Solution in salt aggregates (100–200 micron), the strain rates being 50% to 200% faster in samples containing 10% clays than for clay-free samples. Even the presence of 1% clay increases the strain rate significantly. We propose that clay particles enhance Pressure Solution creep because these microscopic minerals are trapped within the salt particle contacts where they allow faster diffusion of solutes from the particle contacts to the pore space and inhibit grain boundary formation.
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kinetics of crack sealing intergranular Pressure Solution and compaction around active faults
Journal of Structural Geology, 2000Co-Authors: Francois Renard, Jean-pierre Gratier, Bjørn JamtveitAbstract:Geological evidence indicates that fluids play a key role during the seismic cycle. After an earthquake, fractures are open in the fault and in the surroundings rocks. With time, during the interseismic period, the permeability of the fault and the country rocks tends to decrease by gouge compaction and fracture healing and sealing. DisSolution along stylolite seams provides the matter that fills the fractures, whereas intergranular Pressure Solution is responsible for gouge compaction. If these processes are fast enough during the seismic cycle, they can modify the creep properties of the fault. Based on field observations and experimental data, we model the porosity decrease by Pressure Solution processes around an active fault after an earthquake. We arrive at plausible rates of fracture sealing that are comparable to the recurrence time for earthquakes. We also study the sensitivity of these rates to various parameters such as grain size, fracture spacing, and the coeAcient of diAusion along grain