Structure and sedimentology of George VI Ice Shelf, Antarctic Peninsula: implications for ice-sheet dynamics and landform development

Abstract

Sponsorship: NERC RONO: NE/F012896/1Collapse of Antarctic ice shelves in response to a warming climate is well documented, but its legacy in terms of depositional landforms is little known. This paper uses remote-sensing, structural glaciological and sedimentological data to evaluate the evolution of the c. 25000?km2 George VI Ice Shelf, SW Antarctic Peninsula. The ice shelf occupies a north?south-trending tectonic rift between Alexander Island and Palmer Land, and is nourished mainly by ice streams from the latter region. The structure of the ice shelf is dominated by inherited foliation and fractures, and with velocity data indicates a largely compressive flow regime. The formation of a moraine complex at the margin of the ice shelf is controlled by debris entrained within foliation and folds. This englacial debris is of basal origin, and includes both local Mesozoic sedimentary and volcanic lithologies, and exotic crystalline rocks from Palmer Land. Folding of basal ice to a high level in the source glaciers on Palmer Land is required to bring the debris to the surface. These results have implications for understanding flow dynamics of ice shelves under compressive flow, and debris entrainment and moraine formation associated with palaeo-ice shelves.publishersversionPeer reviewe

Recent understanding of Antarctic supraglacial lakes using satellite remote sensing

“…Towards the southerly extent of the Antarctic Peninsula, abundant SGLs occupy parts of the Wilkins Ice Shelf and George VI Ice Shelf during the austral summer (Figure 1) (Braun and Humbert, 2009;Labarbera and MacAyeal, 2011;Lucchitta and Rosanova, 1998;Vaughan et al, 1993). Lakes are largely concentrated on the central part of George VI and their location is controlled by the location of crevasses (Hambrey et al, 2015), and the down-ice migration of surface depressions following the propagation of compressive stresses (Labarbera and MacAyeal, 2011). On Wilkins Ice Shelf, SGLs have been largely confined to localised regions (Lucchitta and Rosanova, 1998;Vaughan et al, 1993), similar to Larsen C. Lakes were visible in MODIS imagery of the northern portion of Wilkins Ice Shelf prior to a major calving event (77km 2 ) in March 2008, immediately following the end of the melt season (Scambos et al, 2009).…”

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“…143 )Modern Pine Island Glacier ice shelf cavity 30 Ice-shelf morainesGently inclined shore or ice-shelf edge parallel ice- cored linear debris accumulations formed around ice shelf edges—Originate from thrusted slabs of glacimarine sediment, folded debris- rich basal ice, and/or the accretion of sea-water and basal marine sediments. Sometimes contain marine organisms that can be datedGeorge VI Ice Shelf 83 ; McMurdo (Minna Bluff), Sorsdal Ice Shelf 84 Landforms of retreating ice shelves Iceberg ploughmarks [26]Cross-cutting, curvilinear to sinuous scour marks. V- shaped in profile often with flanking berms.…”

Automated Mapping of Antarctic Supraglacial Lakes Using a Machine Learning Approach

“…The selection of study sites was based on known supraglacial lake locations (e.g., [20,21,34,[47][48][49]) as well as the visual inspection of satellite imagery on Google Earth Engine. To ensure the spatial transferability of our supraglacial lake detection algorithm, we selected training and test regions evenly distributed across Antarctica containing information on all different types of environments and surface conditions.…”