EGU2020-20512, updated on 21 Apr 2023
https://doi.org/10.5194/egusphere-egu2020-20512
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Grounding Zone of Thwaites Glacier Explored by Icefin

Britney Schmidt1, Keith Nicholls2, Peter Davis2, James Smith2, Kiya Riverman3, David Holland4, Daniel Dichek1, Andrew Mullen1, Justin Lawrence1, Peter Washam1, Aurora Basinski-ferris4, Paul Anker2, Matthew Meister1, Anthony Spears1, Ben Hurwitz1, Enrica Quartini1, Elisabeth Clyne5, Catrin Thomas2, James Wake2, David Vaughn2, and the ITGC Team (MELT & Thwaites Glacier Grounding Zone Downstream teams)*
Britney Schmidt et al.
  • 1Georgia Institute of Technology, Earth & Atmospheric Sciences (britneys@eas.gatech.edu)
  • 2British Antarctic Survey
  • 3University of Oregon
  • 4New York University
  • 5Pennsylvania State University
  • *A full list of authors appears at the end of the abstract

Icefin performed the first long range robotic exploration of the grounding zone of Thwaites Glacier from January 9-12 2020. Icefin was part of the MELT project of the International Thwaites Glacier Collaboration deployed to the grounding zone of Thwaites Glacier, West Antarctica over the period December 2019-February 2020.  MELT is an interdisciplinary project to explore rapid change across the grounding zone, and in particular basal melting.  The subglacial cavity ~2km north of the grounding zone was accessed via hot water drilling on January 7-8, 2020.  Icefin, a hybrid autonomous and remotely operated underwater vehicle designed for sub-ice and borehole operations, conducted over 15km of round-trip data collection under the ice along a section of the glacier from the grounding zone extending to a point 4 km oceanward.   The vehicle collected data with ten different science sensors including cameras, sonars, conductivity/temperature and dissolved oxygen.  Overall, the water column ranged from ~100m downstream that narrowed quickly to an average of 50m that spanned over 2km, to a long segment of ~30m thickness before quickly narrowing over 500m towards the grounding zone. The seafloor structures run roughly parallel to ice flow direction, consisting of furrows, ridges, and grooves in some cases mirrored by the ice structure. The Icefin dives revealed a diverse set of basal ice conditions, with complex geometry, including a range of terraced features, smooth ablated surfaces, crevassing, sediment rich layers of varying kinds, as well as interspersed clear, potentially accreted freshwater ice.  The ocean directly beneath the ice varies spatially, from moderately well-mixed near the grounding zone to highly stratified within and below concavities in the ice downstream.  Sediments along the sea floor range from fine grained downstream to course angular gravel near the grounding zone distributed between larger boulders.  We observed rocky material in the ice that ranged from fine grained layers compressed within the ice to small angular particles volumetrically distributed within ice, to gravel and cobbles, as well as trapped boulders up to meter scale. In addition to the oceanographic, glaciological and sea floor conditions, we also catalogued communities of organisms along the seafloor and ice-ocean interface. We will report the highlights and initial conclusions from Icefin’s in situ data collection, and offer perspectives on change at the grounding zone.

ITGC Team (MELT & Thwaites Glacier Grounding Zone Downstream teams):

Sridhar Anandakrishnan [5], John Paden [6], Eric Rignot [7], Benjamin Yeager [4], Keith Makinson [2]

How to cite: Schmidt, B., Nicholls, K., Davis, P., Smith, J., Riverman, K., Holland, D., Dichek, D., Mullen, A., Lawrence, J., Washam, P., Basinski-ferris, A., Anker, P., Meister, M., Spears, A., Hurwitz, B., Quartini, E., Clyne, E., Thomas, C., Wake, J., and Vaughn, D. and the ITGC Team (MELT & Thwaites Glacier Grounding Zone Downstream teams): The Grounding Zone of Thwaites Glacier Explored by Icefin, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20512, https://doi.org/10.5194/egusphere-egu2020-20512, 2020.

This abstract will not be presented.