Subglacial thermal balance permits ongoing grounding line retreat along the Siple Coast of West Antarctica

• Main Authors: Parizek, Byron R., Alley, Richard B., Hulbe, Christina L.
• Format: Text
• Language: unknown
• Published: PDXScholar 2003
• Subjects: Ice sheets > Antarctica; Glaciers > Antarctica; Ice shelves > Antarctica; Glaciers > Antarctica > Ross Ice Shelf; Geology; Antarctic; West Antarctica; West Antarctic Ice Sheet; Ross Ice Shelf; Siple; Whillans; Siple Coast; Whillans Ice Stream; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves; Ice Stream A; Ice Stream C; Ice Stream D
• Online Access: https://pdxscholar.library.pdx.edu/geology_fac/30; https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1029&context=geology_fac

Changes in the discharge of West Antarctic ice streams are of potential concern with respect to global sea level. The six relatively thin, fast-flowing Ross ice streams are of interest as low-slope end-members among Antarctic ice streams. Extensive research has demonstrated that these "rivers of ice" have a history of relatively high-frequency (óO(100) years), asynchronous discharge variations with evolving lateral boundaries. Amidst this variability, a ~1300 km grounding-line retreat has occurred since the Last GlacialMaximum. Numerical studies of Ice Stream D (Parizek and others, 2002) indicate that a proposed thermal-regulation mechanism(Clarke and Marshall, 1998; Hulbe and MacAyeal,1999; Tulaczyk and others, 2000a,b), which could buffer the West Antarctic ice sheet against complete collapse, may be over-ridden by latent-heat transport within meltwater from beneath inland ice. Extending these studies to Ice Stream A,Whillans Ice Stream and Ice Stream C suggests that further grounding-line retreat contributing to sea-level rise is possible thermodynamically. However, the efficiency of basal water distribution may be a constraint on the system. Because local thermal deficits promote basal freeze-on (especially on topographic highs), observed short-term variability is likely to persist.