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Subglacial geology and geomorphology of the Pensacola-Pole Basin, East Antarctica

Paxman, G.J.G.; Jamieson, S.S.R.; Ferraccioli, F.; Jordan, T.A.; Bentley, M.J.; Ross, N.; Forsberg, R.; Matsuoka, K.; Steinhage, D.; Eagles, G.; Casal, T.G.

Subglacial geology and geomorphology of the Pensacola-Pole Basin, East Antarctica Thumbnail


Authors

F. Ferraccioli

T.A. Jordan

N. Ross

R. Forsberg

K. Matsuoka

D. Steinhage

G. Eagles

T.G. Casal



Abstract

The East Antarctic Ice Sheet (EAIS) is underlain by a series of low‐lying subglacial sedimentary basins. The extent, geology and basal topography of these sedimentary basins are important boundary conditions governing the dynamics of the overlying ice sheet. This is particularly pertinent for basins close to the grounding line wherein the EAIS is grounded below sea level, and therefore potentially vulnerable to rapid retreat. Here, we analyze newly acquired airborne geophysical data over the Pensacola‐Pole Basin (PPB), a previously unexplored sector of the EAIS. Using a combination of gravity, magnetic and ice‐penetrating radar data, we present the first detailed subglacial sedimentary basin model for the PPB. Radar data reveal that the PPB is defined by a topographic depression situated ~500 m below sea level. Gravity and magnetic depth‐to‐source modeling indicate that the southern part of the basin is underlain by a sedimentary succession 2–3 km thick. This is interpreted as an equivalent of the Beacon Supergroup and associated Ferrar dolerites that are exposed along the margin of East Antarctica. However, we find that similar rocks appear to be largely absent from the northern part of the basin, close to the present‐day grounding line. In addition, the eastern margin of the basin is characterized by a major geological boundary and a system of overdeepened subglacial troughs. We suggest that these characteristics of the basin may reflect the behavior of past ice sheets and/or exert an influence on the present‐day dynamics of the overlying EAIS.

Citation

Paxman, G., Jamieson, S., Ferraccioli, F., Jordan, T., Bentley, M., Ross, N., …Casal, T. (2019). Subglacial geology and geomorphology of the Pensacola-Pole Basin, East Antarctica. Geochemistry, Geophysics, Geosystems, 20(6), 2786-2807. https://doi.org/10.1029/2018gc008126

Journal Article Type Article
Acceptance Date May 20, 2019
Online Publication Date May 28, 2019
Publication Date Jun 30, 2019
Deposit Date Mar 27, 2019
Publicly Available Date Mar 29, 2024
Journal Geochemistry, Geophysics, Geosystems
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 20
Issue 6
Pages 2786-2807
DOI https://doi.org/10.1029/2018gc008126

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Published Journal Article (Advance online version) (13.1 Mb)
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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
Advance online version © 2019. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.






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