Preconsolidation of tills and intertill clays by glacial loading in southern Saskatchewan, Canada

Abstract

Preconsolidation of pre-Battleford tills and intertill clays resulted in a narrow range of effective pressures (1800 ± 200 kPa) at 10 sites along a 1300 km transect across southern Saskatchewan. These data suggest an almost invariant loading system that is independent of total ice thickness, which ranged from 1150 to 2000 m. The preconsolidation process apparently took place in a temperate glacier environment. The loading system is characterized as a variable thickness of ice related to distance from the glacier terminus. A steady hydraulic "grade line" sustained a potentiometric surface within the subglacial sediments at an elevation consistently 69–76% of the total ice thickness. This mechanism maintains small fluctuations in effective stress.