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Mid-Holocene thinning of David Glacier, Antarctica: chronology and controls

Stutz, Jamey; Mackintosh, Andrew; Norton, Kevin; Whitmore, Ross; Baroni4, Carlo; Jamieson, Stewart S.R.; Jones, Richard S.; Balco, Greg; Salvatore, Maria Cristina; Casale, Stefano; Lee, Jae Il; Seong, Yeong Bae; McKay, Robert; Vargo, Lauren J.; Lowry, Daniel; Spector, Perry; Christl, Marcus; Ochs, Susan Ivy; Nicola, Luigia Di; Iarossi, Maria; Stuart, Finlay; Woodruff, Tom

Mid-Holocene thinning of David Glacier, Antarctica: chronology and controls Thumbnail


Authors

Jamey Stutz

Andrew Mackintosh

Kevin Norton

Ross Whitmore

Carlo Baroni4

Richard S. Jones

Greg Balco

Maria Cristina Salvatore

Stefano Casale

Jae Il Lee

Yeong Bae Seong

Robert McKay

Lauren J. Vargo

Daniel Lowry

Perry Spector

Marcus Christl

Susan Ivy Ochs

Luigia Di Nicola

Maria Iarossi

Finlay Stuart

Tom Woodruff



Abstract

Quantitative satellite observations only provide an assessment of ice sheet mass loss over the last four decades. To assess long-term drivers of ice sheet change, geological records are needed. Here we present the first millennial-scale reconstruction of David Glacier, the largest East Antarctic outlet glacier in Victoria Land. To reconstruct changes in ice thickness, we use surface exposure ages of glacial erratics deposited on nunataks adjacent to fast-flowing sections of David Glacier. We then use numerical modelling experiments to determine the drivers of glacial thinning. Thinning profiles derived from 45 10Be and 3He surface exposure ages show David Glacier experienced rapid thinning of up to 2 m/yr during the mid-Holocene (∼ 6.5 ka). Thinning slowed at 6 ka, suggesting the initial formation of the Drygalski Ice Tongue at this time. Our work, along with ice thinning records from adjacent glaciers, shows simultaneous glacier thinning in this sector of the Transantarctic Mountains occurred 4–7 kyr after the peak period of ice thinning indicated in a suite of published ice sheet models. The timing and rapidity of the reconstructed thinning at David Glacier is similar to reconstructions in the Amundsen and Weddell embayments. To identify the drivers of glacier thinning along the David Glacier, we use a glacier flowline model designed for calving glaciers and compare modelled results against our geological data. We show that glacier thinning and marine-based grounding-line retreat are controlled by either enhanced sub-ice-shelf melting, reduced lateral buttressing or a combination of the two, leading to marine ice sheet instability. Such rapid glacier thinning events during the mid-Holocene are not fully captured in continental- or catchment-scale numerical modelling reconstructions. Together, our chronology and modelling identify and constrain the drivers of a ∼ 2000-year period of dynamic glacier thinning in the recent geological past.

Citation

Stutz, J., Mackintosh, A., Norton, K., Whitmore, R., Baroni4, C., Jamieson, S. S., …Woodruff, T. (2021). Mid-Holocene thinning of David Glacier, Antarctica: chronology and controls. The Cryosphere, 15(12), 5447-5471. https://doi.org/10.5194/tc-15-5447-2021

Journal Article Type Article
Acceptance Date Oct 17, 2021
Online Publication Date Dec 7, 2021
Publication Date 2021
Deposit Date Dec 7, 2021
Publicly Available Date Mar 29, 2024
Journal The Cryosphere
Electronic ISSN 1994-0424
Publisher Copernicus Publications
Peer Reviewed Peer Reviewed
Volume 15
Issue 12
Pages 5447-5471
DOI https://doi.org/10.5194/tc-15-5447-2021

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