Ice Stream C slowdown is not stabilizing West Antarctic Ice Sheet

• Main Authors: S Anandakrishnan, Rb Alley, Rw Jacobel, H Conway
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: Antarctic; Ross Sea; West Antarctica; West Antarctic Ice Sheet; Siple; Siple Dome; Siple Coast; Antarc*; Antarctica; Ice Sheet; Ice Stream B; Ice Stream C
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.366.9711; http://www.stolaf.edu/other/cegsic/publications/Anandakrishnan et al.pdf

Changes in the flow of ice stream C likely indicate a continuing slow drawdown of the Siple Coast of West Antarctica rather than a stabilizing feedback. The downglacier part of ice stream C, West Antarctica largely stagnated over the last few centuries, while upglacier regions continue to flow vigorously. Stagnation likely occurred near Siple Dome before the entirety of the downglacier part slowed. Numerous data sets show that the slow-moving part of the ice stream is restrained largely by small, localized basal “sticky spots”. The sticky spots are separated by extensive regions of soft till containing high-pressure liquid water. The soft till slows the transmission of ice-flow changes caused by microearthquakes or by tide-height in the Ross Sea, suggestive of viscous behavior. Near the transition from fast-moving well-lubricated ice to slow-moving ice with basal seismicity, a hydrologic potential map indicates that basal water flowing in from the catchment is diverted away from the slow-moving ice to ice stream B. This diversion could have been caused by a flattening of the surface slope over time in response to the headward growth of ice stream C drawing down the inland ice. Previous mass-balance estimates indicate that the combined B-C drainage most likely is thinning slowly, similar to the rest of the Siple Coast, and consistent with the inland water continuing to lubricate fast ice flow, but now concentrated in ice stream B.