Swath bathymetry images of subglacial meltwater features in the Amundsen Sea Embayment

Increasing evidence for an elaborate subglacial drainage network underneath modern Antarctic ice sheets suggests that its basal meltwater has an important influence on ice stream flow. Swath bathymetry surveys from previously glaciated continental margins display morphological features indicative of meltwater flow in areas of paleo ice stream movements. Over the last few years several expeditions into the eastern Amundsen Sea have investigated the paleo ice streams connected to the Pine Island and Thwaites Glaciers. Unusually favorable sea ice conditions in early 2009 and 2010 allowed us to acquire high-resolution swath bathymetry over large, coherent areas of the of the Thwaites and Pine Island paleo ice streams. Together with previous collections, these data reveal details of a rough topography on the inner shelf including several deep channels that connect a series of deeper basins. This complex basin and channel network is indicative of meltwater flow beneath the paleo-Pine Island and Thwaites ice streams, along with substantial subglacial water inflow from the east. This meltwater could have enhanced ice flow over the rough bedrock topography. Meltwater features diminish with the onset of linear features north of the basins. Similar features have previously been observed at several other areas including the Getz trough in the central Amundsen Sea and Marguerite Bay in the Antarctic Peninsula. This suggests that these features and the processes that created them are common around the margin. A comparison of the different features allows the identification of the dominant processes and the creation of a conceptual model of subglacial meltwater flow and its interaction with the ice and underlying substrate.