Schlegel, R., Brisbourne, A.M., Smith, A.M. et al. (4 more authors) (2024) Subglacial bedform and moat initiation beneath Rutford Ice Stream, West Antarctica. Geomorphology, 458. 109207. ISSN 0169-555X
Abstract
The accuracy of sea-level rise predictions is highly dependent on reliably understanding the subglacial environment beneath ice streams. Bedforms result from the interaction between ice and its substrate, and therefore have the potential to shed light on poorly understood basal conditions influencing ice dynamics. However, theoretical models of bedform formation are often based on observations from deglaciated areas or from sparsely-sampled geophysical surveys over glaciated regions. Here, we use high-resolution three- and two-dimensional radar and seismic data to reveal details of the initiation and evolution of a subglacial bedform beneath Rutford Ice Stream, West Antarctica. Radar surveys at 20 m and 50 m line spacing allow detailed imaging of bed topography, including a moat up to 55 m deep, surrounding the upstream end of a 50-m high and >18-km long bedform. Many models rely on either a topographical or a locally resistant seed point to initiate bedform formation. The bedform described here is mostly composed of soft sediment (porosity >0.3) and lacks a boulder or outcrop, suggesting the bedform initiated without a topographic seed point. Sediment at the upstream end of bedforms appears stiffer over a distance of 2.3 km. We suggest sediment inhomogeneities in the initially flat bed cause the deposition of sediment, which, assuming resistant enough, acts as a seed point for bedform extension and moat erosion. The moat's geometry and its truncation of other bedforms suggest that it was eroded after the deposition of surrounding bedforms. These observations from a modern ice stream deliver information of subglacial processes involved in the initiation as well as in situ high-resolution topography and properties of bedforms and moats. Using these observations numerical models can be tested and developed accordingly.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | Elongated subglacial bedforms and moats; Bedform initiation and evolution; Modern Ice Stream; Rutford Ice Stream; West Antarctica; 3D radar data; Acoustic impedance |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 05 Jul 2024 15:43 |
Last Modified: | 05 Jul 2024 15:43 |
Published Version: | https://www.sciencedirect.com/science/article/pii/... |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.geomorph.2024.109207 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:213813 |
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