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Rock glacier characteristics serve as an indirect record of multiple alpine glacier advances in Taylor Valley, Antarctica

Winsor, Kelsey and Swanger, Kate M. and Babcock, Esther and Valletta, Rachel D. and Dickson, James L. (2020) Rock glacier characteristics serve as an indirect record of multiple alpine glacier advances in Taylor Valley, Antarctica. The Cryosphere, 14 (1). pp. 1-16. ISSN 1994-0424. https://resolver.caltech.edu/CaltechAUTHORS:20200116-090202970

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Abstract

The geomorphic record indicates that alpine glaciers in the McMurdo Dry Valleys of southern Victoria Land, Antarctica, appear to advance during interglacial periods in response to ice-free conditions in the Ross Sea. Few records of these advances are preserved and/or subaerially exposed, complicating the interpretations of regional glacier response to climate changes. Here, we present geophysical and geochemical analyses of a rock glacier that originates from icefalls fed by alpine Doran Glacier in central Taylor Valley. The rock glacier exhibits a trend of increased weathering of granitic clasts via ventifaction and grussification down-flow. Meltwater ponds on the rock glacier exhibit variable salinity that ranges from freshwater to higher than seawater, with the highest salinity pond near the rock glacier toe. Ground-penetrating radar analyses reveal the feature to possess a primarily clean ice interior, with layers of englacial debris. Stable isotopic data from three ice cores support a glacial origin for the ice within the rock glacier. These data suggest that the current morphology of the rock glacier is the result of multiple events of increased ice contribution caused by advances of Doran Glacier, which is the main source of ice to the rock glacier. We therefore demonstrate the potential of ice-cored rock glaciers to record multiple advances and retreats of Dry Valley glaciers, permitting the interpretation of glacial responses to Pleistocene and Holocene climate change even where direct records are not present.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.5194/tc-14-1-2020DOIArticle
https://doi.org/10.5194/tc-14-1-2020-supplementDOISupplement
ORCID:
AuthorORCID
Valletta, Rachel D.0000-0001-9536-7099
Additional Information:© 2020 Author(s). This work is distributed under the Creative Commons Attribution 4.0 License. Published by Copernicus Publications on behalf of the European Geosciences Union. Received: 03 Jun 2019 – Discussion started: 18 Jun 2019 – Revised: 02 Nov 2019 – Accepted: 04 Nov 2019 – Published: 02 Jan 2020. Data availability: All geochemical data are provided in the Supplement. The supplement related to this article is available online at: https://doi.org/10.5194/tc-14-1-2020-supplement. Author contributions: All authors participated in field observations, GPR surveying, and ice core collection. KMS organized and led the field campaign. KW and KMS collected soil and ice hand samples. EB directed GPR surveying and performed all GPR data processing. KW processed samples for major ion analyses. KW and KMS processed samples for stable isotope analyses. KW, KMS, and EB prepared the paper, created figures, and made tables. The authors declare that they have no conflict of interest. The authors would like to thank the McMurdo Station support staff, especially those at the Berg Field Center, Petroleum Helicopters International, and the Crary Laboratory, for assistance during the field season. Geoff Hargreaves and crew were of great assistance in subsampling ice cores at the National Ice Core Laboratory. Fred Luiszer (University of Colorado-Boulder) analyzed samples for major ions and Robert Michener (Boston University) analyzed samples for stable isotopes. Useful discussions were had with Maciej Obryk. We also thank the two anonymous reviewers. This research has been supported by the United States National Science Foundation Office of Polar Programs (grant no. 1341284). This paper was edited by Peter Morse and reviewed by two anonymous referees.
Funders:
Funding AgencyGrant Number
NSFOPP-1341284
Issue or Number:1
Record Number:CaltechAUTHORS:20200116-090202970
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200116-090202970
Official Citation:Winsor, K., Swanger, K. M., Babcock, E., Valletta, R. D., and Dickson, J. L.: Rock glacier characteristics serve as an indirect record of multiple alpine glacier advances in Taylor Valley, Antarctica, The Cryosphere, 14, 1–16, https://doi.org/10.5194/tc-14-1-2020, 2020.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100754
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:16 Jan 2020 17:21
Last Modified:16 Jan 2020 17:21

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