Imaging brine infiltration and basal marine ice in Larsen C Ice Shelf, Antarctic Peninsula, from borehole measurements and transient electromagnetics

Killingbeck, Siobhan F., Kulessa, Bernd, Miles, Katie E., Hubbard, Bryn, Luckman, Adrian, Thompson, Sarah S., Jones, Glenn and Galton‐Fenzi, Benjamin K. 2025. Imaging brine infiltration and basal marine ice in Larsen C Ice Shelf, Antarctic Peninsula, from borehole measurements and transient electromagnetics. Geophysical Research Letters 52 (17) , e2025GL115908. 10.1029/2025gl115908

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Abstract

The presence and nature of marine ice in ice shelves is important, yet difficult to determine. We present transient electromagnetic results spanning 10 km across a suture zone of Larsen C Ice Shelf (LCIS), Antarctica, supported by central borehole measurements. Our results indicate the presence of two ice-shelf layers. The uppermost layer, ∼300 m thick, has resistivity 103−106 Ωm. We interpret this as meteoric ice, overlying a lower shelf layer 25–56 m thick with resistivity 3–20 Ωm, consistent with permeable basal marine ice. This reconstruction closely matches modeled marine-ice thicknesses in the area. The porosity of this layer is 0.18–0.40, higher than measured farther down-flow, suggesting the layer consolidates once formed. Within the upper layer at 78.5 m depth, we identify a 2.5 m thick layer, likely linked to brine infiltration. These heterogeneities in ice shelf properties should be accounted for in future LCIS stability assessments.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Earth and Environmental Sciences
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/
Publisher:	Wiley
ISSN:	0094-8276
Date of First Compliant Deposit:	3 September 2025
Date of Acceptance:	1 August 2025
Last Modified:	04 Sep 2025 13:22
URI:	https://orca.cardiff.ac.uk/id/eprint/180848

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