Over the last three decades, Antarctic Peninsula Ice Shelves have shown a pattern of sustained retreat, often ending in catastrophic and rapid breakup. This study provides a detailed analysis of the structures and dynamics of Bach, George VI and Stange Ice Shelves, situated on the southwest Antarctic Peninsula, to determine their current and future stability on the premise that glaciological changes can be identified well in advance of final breakup phases. Spatial extent and glaciological surface features were mapped for each ice shelf from 1973 to 2010 using optical and radar satellite images to assess their structural stability, structural evolution and historical dynamics. A combination of InSAR and feature tracking methods has been used to assess the recent dynamic configurations of the ice shelves from 1989 to 2010, with repeat ICESat measurements used to evaluate their vertical changes from 2003 to 2008. On Bach Ice Shelf, the formation of two large fractures near the ice front is linked to widespread thinning (~2 ma-1) and sustained retreat (~360 km2). It is postulated that iceberg calving along these fractures will alter the frontal geometry sufficiently to promote enhanced, irreversible retreat within the next decade. On George VI Ice Shelf, acceleration is observed at both ice fronts linked to a release of back-stresses through continued ice loss (1995 km2 in total). The most significant changes are recorded at its southern ice front, with ice flow accelerating up to 360% between ca. 1989 and ca. 2010, coupled with widespread rifting and a mean thinning rate of 2.1 ma-1. On Stange Ice Shelf, shear-induced fracturing was observed between two flow units, also linked to widespread thinning (~4.2 ma-1) illustrating a response of southwest Antarctic Peninsula Ice Shelves within the proposed limit of viability. A semi-quantitative assessment reveals that the southern margin of George VI Ice Shelf is most susceptible to rapid retreat, whilst its northern ice front, Bach Ice Shelf and the northern front of Stange Ice Shelf are more vulnerable than those situated on the east Antarctic Peninsula.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:577700 |
| Date | January 2013 |
| Creators | Holt, Thomas Owen |
| Contributors | Glasser, Neil ; Quincey, Duncan Joseph |
| Publisher | Aberystwyth University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/2160/c64f9e1d-af1c-49e8-be1c-d3252bcaf409 |
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