Evidence for water storage and drainage at the base of the Laurentide ice sheet, south-central Alberta, Canada

Abstract

Abstract Glaciogenic sediment up to 70 m thick is exposed in preglacial valley fills in south-central Alberta. The two youngest facies are comprised of glaciolacustrine sediments overlain by a subglacial till. Conformable relationships with the till and topographic relationships support a subglacial origin for the lake sediments. As these facies are restricted to the preglacial valley system, it is suggested that the preglacial valleys of south-central Alberta acted as natural cavities at the base of the Laurentide ice sheet. Sedimentology suggests these filled and drained often.