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Factors Affecting Pressure Solution

As discussed in the section on 'Micro-mechanisms of Pressure Solution,' pressure solution involves three steps: dissolution, diffusion, and precipitation. The slowest of the three steps determines the rate of pressure solution. There are many factors affecting either one, two, or all three steps. The most important one is probably the mineral composition, which determines the solubility of the rock under pressure. Presence of water, grain size, and clay content affect the transportation of the dissolved material down the concentration gradient. Pressure and temperature are also factors to be considered. The time it takes to form pressure solution seams is negligible in geological time scale but considerably longer for human time scale.

Rutter (1983) provided a governing equation for pressure solution (in Equation 1). The constant A depends on the geometry of the interface; and is 32 for a circular, plane interface between two grains, normal to the applied stress. The temperature dependence of the process resides in L(alpha), as does the effect of solubility of the solid in a stressed water film, and any effects that applied stress might have on ion mobility. The effective water film thickness also depends on the stress, so that the overall stress sensitivity to strain rate may be complex.

Governing equation of the strain rate of pressure solution. e is the strain rate in the direction of the applied stress; A is a dimensionless constant; L(alpha) is the phenomenology coefficient; sigma is the applied uniaxial stress; V(alpha) is the volume of the stressed solid; w is the effective thickness of the inter-granular diffusion window; and d is the grain diameter. From Rutter (1983).Equation 1. Governing equation of the strain rate of pressure solution. e is the strain rate in the direction of the applied stress; A is a dimensionless constant; L(alpha) is the phenomenology coefficient; sigma is the applied uniaxial stress; V(alpha) is the volume of the stressed solid; w is the effective thickness of the inter-granular diffusion window; and d is the grain diameter. From Rutter (1983).
Types of Factors Affecting Pressure Solution:
Pressure Solution and the Role of WaterPressure Solution and Pore Fluid ChemistryPressure Solution and TemperaturePressure Solution and PressurePressure solution and Clay ContentPressure Solution and Grain SizePressure Solution and Time (Rate)
Reference:

Rutter, E.H., 1983. Pressure solution in nature, theory and experiment. Journal of Geological Society 140 (Sep): 725-740.



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