ABSTRACT

Recent deposits of Athabasca Glacier in Alberta. Canada, were divided into five environments on the basis of sedimentary. properties. Particle-size distribution, roundness, striations, fabric, and lithologic composition were used to distinguish between basal till. recessional-moraine till, lateral-moraine till, ablation till, and outwash. Mean particle size and sorting increase in the above order, and skewness also varies with environment. Clast roundness decreases in the same order, except that outwash has the most rounded clasts and recessional-moraine till is equivalent to basal till. Percent of striated clasts decreases in the above order, although recessional-moraine and basal tills are similar. Fabrics of basal tills parallel the direction of ice flow and are much stronger than hose of other environments. Ablation-till fabrics tend to be transverse to flow. Fabrics on the distal flanks of lateral and recessional moraines are transverse to the crest, whereas proximal fabrics show parallel as well as transverse modes. Quartzite, which crops out mainly beneath the glacier, serves as an indicator of subglacially derived debris.