Pressure Solution in Sedimentary Basins: Effect of Temperature Gradient

TL;DR

This paper investigates how temperature gradients affect pressure solution in sedimentary basins, deriving new relations and analyzing the process's dynamics through numerical and asymptotic methods.

Contribution

A new derivation of viscous compaction relation considering realistic boundary conditions and analysis of pressure solution behavior under varying temperature gradients.

Findings

Higher thermal gradients accelerate porosity reduction.

Pressure solution completes faster at shallower depths in high-temperature environments.

Model predictions agree well with real sediment data.

Abstract

Pressure solution is an important process in sedimentary basins, and its behaviour depends mainly on the sediment rheology and temperature distribution. The compaction relation of pressure solution is typically assumed to be a viscous one and is often written as a relationship between effective stress and strain rate. A new derivation of viscous compaction relation is formulated based on more realistic boundary conditions at grain contacts. A nonlinear diffusion problem with a moving boundary is solved numerically and a simple asymptotic solution is given to compare with numerical simulations. Pressure solution is significantly influenced by the temperature gradient. Porosity reduction due to pressure solution is enhanced in an environment with a higher thermal gradient, while porosity decreases much slowly in the region where the thermal gradient is small. Pressure solution tends to complete more quickly at shallower depths and earlier time in higher temperature environment than that in a low one. These features of pressure solution in porous sediments are analysed using a perturbation method to get a solution for the steady state. Comparison with real data shows a reasonably very good agreement.