Subglacial conditions at a sticky spot along Kamb Ice Stream, West Antarctica

• Main Authors: Peters, LE, Anandakrishnan, S
• Format: Conference Object
• Language: English
• Published: U.S. Geological Survey 2007
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Kamb Ice Stream; West Antarctica; Antarc*; Antarctica
• Online Access: http://pubs.usgs.gov/of/2007/1047/; https://doi.org/10.3133/ofr20071047SRP097; http://ecite.utas.edu.au/103888

We present the results of a seismic reflection experiment performed transverse to flow a few tens ofkilometers above the main trunk of Kamb Ice Stream, West Antarctica, where we image a basal high surrounded byvariable subglacial conditions. This high rises as much as 200 m above the surrounding bed, acting as a majorsticking point that resists fast flow. Application of the amplitude variation with offset (AVO) seismic technique hashighlighted regions of frozen sediments along our profile, suggesting that the ice stream is experiencing basalfreeze-on in the region. The bedrock high appears to be at least partially draped in sediment cover, with aconcentrated area of weak, dilatant till flanking one edge. This dilatant till is further dispersed along our profile,though it does not possess enough continuity to maintain streaming ice conditions. These results support thehypothesis that the ongoing shutdown of Kamb Ice Stream is due to a loss in continuous basal lubrication.