The glacial geomorphology of western Dronning Maud Land, Antarctica

Abstract

Reconstructing the response of present-day ice sheets to past global climate change is important for constraining and refining the numerical models which forecast future contributions of these ice sheets to sea-level change. Mapping landforms is an essential step in reconstructing glacial histories. Here we present a new map of glacial landforms and deposits on nunataks in western Dronning Maud Land, Antarctica. Nunataks are mountains or ridges that currently protrude through the ice sheet and may provide evidence that they have been wholly or partly covered by ice, thus indicating a formerly more extensive (thicker) ice sheet. The map was produced through a combination of mapping from Worldview satellite imagery and ground validation. The sub-metre spatial resolution of the satellite imagery enabled mapping with unprecedented detail. Ten landform categories have been mapped, and the landform distributions provide evidence constraining spatial patterns of a previously thicker ice sheet.

Ice surface changes during recent glacial cycles along the Jutulstraumen and Penck Trough ice streams in western Dronning Maud Land, East Antarctica

“…3). A till drape covers the lowermost part of the saddle (Newall et al, 2020). Only occasional erratics were observed at higher elevation on this ridge and on the easternmost nunatak.…”

“…1) indicate that the EAIS was thicker than today, with the magnitude of ice-sheet thickening increasing from <50 m in the area around Scharffenbergbotnen in Heimefrontfjella (ca. 130 km inland from the present-day grounding line; Lintinen and Nenonen, 1997;Hättestrand and Johansen, 2005;Newall et al, 2020) to >700 m above the present-day ice surface at the coastal nunatak Plogen, Vestfjella (Lintinen 1996;Lintinen and Nenonen, 1997). Radiocarbon dates on the basal layers of regurgitated stomach oil deposits (mumiyo) from snow petrel (Pagodroma nivea) nesting sites point to ice-free conditions since at least 0.7-7.8 cal ka BP (reported conventional radiocarbon ages: 2.1-8.2 ka; Lintinen and Nenonen, 1997) at nesting sites 100-230 m above the present ice surface at Skuafjellet in Vestfjella.…”

“…A few dispersed erratics were observed on the northernmost nunatak. The southernmost nunatak protrudes the present-day ice partly due to a large windscoop depressing the ice sheet surface in its vicinity (Newall et al, 2020). Snow cover on the ice surface around the nunataks is minimal and blue ice areas dominate to the west.…”

“…Glacial striations occur in a S-N direction. Sporadic erratic cobbles are distributed across the nunatak, while a patchy till cover is present on a small plateau to the north and on the northern slope (Newall et al, 2020). The ice surface to the west is dominated by blue ice with some supraglacial debris.…”

Geomorphology of Ulu Peninsula, James Ross Island, Antarctica

“…Davies et al, 2013;Yildirim, 2020) and glacially related landforms (e.g. Newall et al, 2020) in Antarctica from remotely-sensed imagery has already been well established, with Chandler et al (2018) providing a comprehensive analysis of prevailing approaches and best practices. The geomorphological mapping of the northern Ulu Peninsula undertaken in this study combines new higher-resolution mapping at an unparalleled scale for the Antarctic Peninsula region.…”