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Bed conditions of Pine Island Glacier, West Antarctica
| Content Provider | Semantic Scholar |
|---|---|
| Author | Brisbourne, A. M. Smith, Andrew M. Vaughan, David G. King, Edward Davies, Damon Bingham, Robert G. Smith, E. C. Nias, Isabel J. Rosier, Sebastian H. R. |
| Copyright Year | 2017 |
| Abstract | Although 90% of Antarctica's discharge occurs via its fast-flowing ice streams, our ability to project future ice-sheet response has been limited by poor observational constraints on the ice-bed conditions used in numerical models to determine basal slip. We have helped address this observational deficit by acquiring and analysing a series of seismic reflection profiles to determine basal conditions beneath the main trunk and tributaries of Pine Island Glacier (PIG), West Antarctica. Seismic profiles indicate large-scale sedimentary deposits. Combined with seismic reflection images, measured acoustic impedance values indicate relatively uniform bed conditions directly beneath the main trunk and tributaries, comprising a widespread reworked sediment layer with a dilated sediment lid of minimum thickness 1.5 ± 0.4 m. Beneath a slow-moving inter-tributary region, a discrete low-porosity sediment layer of 7 ± 3 m thickness is imaged. Despite considerable basal topography, seismic observations indicate that a till layer at the ice base is ubiquitous beneath PIG, which requires a highly mobile sediment body to maintain an abundant supply. These results are compatible with existing ice-sheet models used to invert for basal shear stress: existing basal conditions upstream will not inhibit further rapid retreat of PIG if the high-friction region currently restraining flow, directly upstream of the grounding line, is breached. However, small changes in the pressure regime at the bed, as a result of stress reorganisation following retreat, may result in a less-readily deformable bed and conditions which are less likely to maintain high ice-flow rates. |
| Starting Page | 419 |
| Ending Page | 433 |
| Page Count | 15 |
| File Format | PDF HTM / HTML |
| DOI | 10.1002/2016JF004033 |
| Volume Number | 122 |
| Alternate Webpage(s) | https://www.research.ed.ac.uk/portal/files/30210193/30210075._AAM._Bingham..pdf |
| Alternate Webpage(s) | https://www.geos.ed.ac.uk/homes/rbingha2/46_2016_Brisbourne.pdf |
| Alternate Webpage(s) | http://www.research.ed.ac.uk/portal/files/30210193/30210075._AAM._Bingham..pdf |
| Alternate Webpage(s) | http://nrl.northumbria.ac.uk/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf |
| Alternate Webpage(s) | https://doi.org/10.1002/2016JF004033 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
