Subglacial Meltwater Channel Systems and Ice Sheet Overriding, Asgard Range, Antarctica

ABSTRACT

Various morphological features in the mountain ranges of the Dry Valleys region have been interpreted as reflecting late Tertiary overriding by an expanded East Antarctic Ice Sheet. Such features include large-scale stoss and lee topography, and anastomosing systems of channels and potholes. Alternative explanations for the features have been suggested and throw some doubt on the overriding hypothesis. This paper investigates channels and potholes in part of the Asgard Range in some detail and concludes that they do indeed reflect overriding ice. The channels are subglacial meltwater systems reflecting ice flow across the mountains from southwest to northeast. The channels were probably cut by sudden outbursts of meltwater beneath a local warm-based zone within a predominantly cold-based ice sheet.