Imaging and modelling nanoscale dynamics of mineral-mineral and mineral-fluid interfaces during mechano-chemical transformations

Abstract

Nanoscale interactions at mineral-fluid interfaces are important for processes occurring at the Earth's crust. Mineral dissolution occurs when a mineral is in contact with a fluid over time and can be observed by a change in mass. For dissolution to proceed, a fluid must be in contact with the crystal surface. If the mineral is not in contact with the fluid, the rock must provide a pathway to the mineral by a fracture or a fracture network. The projects in this thesis have focused on dissolution kinetics and fracturing, and the results indicates that the access of water to a reacting surface might be limited by the compressive stress. When the stress increases, this might shut off the water supply which will limit mineral dissolution and hydration of minerals. However, when the compressive stress is smaller, there will be a constant water flow to the reacting surface, and dissolution and hydration reactions might progress. If the hydration reaction occurs with a volume increase, the surrounding rock might fracture. These fractures can propagate through the crystal as straight, oscillating or branching cracks, which cause damage in the surrounding material.