Abstract
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.
Highlights
The mapping of areas currently and formerly covered by glaciers and ice sheets is a key component in reconstructing past ice extent and assessing potential future responses to a changing climate (e.g. Blomdin et al, 2016; Clark et al, 2018; Fu et al, 2012; Heyman et al, 2008; Stokes et al, 2015; Stroeven et al, 2016)
Detailed mapping of glacial deposits and landforms on nunataks – mountain summits protruding through the ice sheet surface – was performed to investigate and quantify the past vertical extent of the East Antarctic Ice Sheet (EAIS) in this area, and to guide sample collection for cosmogenic nuclide (CN) surface exposure dating to constrain the timing of ice thickness fluctuations
The map product is intended as a representation of the glacial geomorphology across western Dronning Maud Land (DML) and readers are guided towards the shapefiles in order to study in detail the glacial geomorphology of this region
Summary
The mapping of areas currently and formerly covered by glaciers and ice sheets is a key component in reconstructing past ice extent and assessing potential future responses to a changing climate (e.g. Blomdin et al, 2016; Clark et al, 2018; Fu et al, 2012; Heyman et al, 2008; Stokes et al, 2015; Stroeven et al, 2016). With models predicting that Antarctica will contribute >1 m to global sea-level rise by 2100, and >15 m by 2500 if greenhouse gas emissions continue to increase throughout the twenty-first century (DeConto & Pollard, 2016), it is important to improve our knowledge of how Antarctic ice behaved in response to past periods of climate change. Geologically-constrained ice sheet reconstructions are critical to determining the response of Antarctic ice to changing atmospheric and ocean temperatures. This is because these ice sheet reconstructions inform numerical ice sheet models and improve their ability to predict the timing and pattern of future ice reduction and consequent sea-level rise. The vast area and harsh environment present significant accessibility challenges, the mapping has been completed predominantly by remote sensing from very high-resolution satellite imagery, together with field visits to several ground validation locations
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