Topographic Controls on Channelized Meltwater in the Subglacial Environment

Abstract

Realistic characterization of subglacial hydrology necessitates knowledge of the range in form, scale, and spatiotemporal evolution of drainage networks. A relict subglacial meltwater corridor on the deglaciated Antarctic continental shelf encompasses 80 convergent and divergent channels, many of which are hundreds of meters wide and several of which lack a definable headwater source. Without significant surface-melt contributions to the bed like similarly described landforms in the Northern Hemisphere, channelized drainage capacity varies non-systematically by three orders of magnitude downstream. This signifies apparent additions and losses of basal water to the bed-channelized system that relates to bed topography. Larger magnitude grounding-line retreat events occurred while the channel system was active than once channelized drainage had ceased. Overall, this corridor demonstrates that meltwater drainage styles co-exist in time and space in response to bed topography, with prolonged impacts on grounding-line behavior.