Viscoelastic behaviour of a clay mineral system with a liquid phase at high pressures and temperatures

We conducted dynamic viscoelastic measurements on three clay minerals, kaolinite, illite and smectite with water. These concentrated (dense) suspension systems of clay minerals were investigated using a high-temperature and high-fluid-pressure rheometer to determine their viscoelastic properties, which help further the understanding of tectonic and non-tectonic phenomena in the shallow unconsolidated portion of the lithosphere. Our results suggested that the rheological properties resulting from the network structure of the clay mineral were temperature, pressure and peak shear strain rate dependent. In addition, it was observed during this study that the amount of change in the phase angle varied systematically with the type of clay mineral. This suggests that the viscoelastic behaviour of unconsolidated systems saturated with fluid varies with the type of clay minerals that compose it. (Abstract)