Abrupt Holocene ice loss due to thinning and ungrounding in the Weddell Sea Embayment ...

• Main Authors: Grieman, Mackenzie, Nehrbass-Ahles, Christoph, Hoffmann, Helene, Bauska, Thomas, King, Amy, Mulvaney, Robert, Rhodes, Rachael, Rowell, Isobel, Thomas, Elizabeth, Wolff, Eric
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2024
• Subjects: 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 3705 Geology; 13 Climate Action; Antarctic; Ronne Ice Shelf; Skytrain Ice Rise; Weddell; Weddell Sea; West Antarctic Ice Sheet; Antarc*; ice core; Ice Sheet; Ice Shelf
• Online Access: https://dx.doi.org/10.17863/cam.105369; https://www.repository.cam.ac.uk/handle/1810/363154

The extent of grounded ice and buttressing by the Ronne Ice Shelf, which provides resistance to the outflow of ice streams, moderate West Antarctic Ice Sheet stability. During the Last Glacial Maximum, the ice sheet advanced and was grounded near the Weddell Sea continental shelf break. The timing of subsequent ice sheet retreat and the relative roles of ice shelf buttressing and grounding line changes remain unresolved. Here we use an ice core record from grounded ice at Skytrain Ice Rise to constrain the timing and speed of early Holocene ice-sheet retreat. Measured δ18O and total air content suggest that the surface elevation of Skytrain Ice Rise decreased by about 450 m between 8.2 to 8.0 ka BP (±0.13 ka). We attribute this elevation change to dynamic thinning due to flow changes induced by the ungrounding of ice in the area. Ice core sodium concentrations suggest that the ice front of this ungrounded ice shelf then retreated about 270 km (±30 km) from 7.7 to 7.3 ka BP. These centennial-scale changes ...