Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica ...

• Main Authors: Macdonald, GJ, Banwell, AF, Willis, IANC, Mayer, DP, Goodsell, B, Macayeal, DR
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2019
• Subjects: Glacier hydrology; Ice shelves; Supraglacial debris; Austral; McMurdo Ice Shelf; Antarc*; Antarctica; Ice Shelf; Ice Shelves
• Online Access: https://dx.doi.org/10.17863/cam.37941; https://www.repository.cam.ac.uk/handle/1810/290741

ABSTRACTSurface debris covers much of the western portion of the McMurdo Ice Shelf and has a strong influence on the local surface albedo and energy balance. Differential ablation between debris-covered and debris-free areas creates an unusual heterogeneous surface of topographically low, high-ablation, and topographically raised (‘pedestalled’), low-ablation areas. Analysis of Landsat and MODIS satellite imagery from 1999 to 2018, alongside field observations from the 2016/2017 austral summer, shows that pedestalled relict lakes (‘pedestals’) form when an active surface meltwater lake that develops in the summer, freezes-over in winter, resulting in the lake-bottom debris being masked by a high-albedo, superimposed, ice surface. If this ice surface fails to melt during a subsequent melt season, it experiences reduced surface ablation relative to the surrounding debris-covered areas of the ice shelf. We propose that this differential ablation, and resultant hydrostatic and flexural readjustments of the ice ...