TY - JOUR
T1 - Mid-Holocene thinning of David Glacier, Antarctica
T2 - Chronology and controls
AU - Stutz, Jamey
AU - Mackintosh, Andrew
AU - Norton, Kevin
AU - Whitmore, Ross
AU - Baroni, Carlo
AU - Jamieson, Stewart S.R.
AU - Jones, Richard S.
AU - Balco, Greg
AU - Salvatore, Maria Cristina
AU - Casale, Stefano
AU - Lee, Jae Il
AU - Seong, Yeong Bae
AU - McKay, Robert
AU - Vargo, Lauren J.
AU - Lowry, Daniel
AU - Spector, Perry
AU - Christl, Marcus
AU - Ochs, Susan Ivy
AU - Di Nicola, Luigia
AU - Iarossi, Maria
AU - Stuart, Finlay
AU - Woodruff, Tom
N1 - Funding Information:
Field work, AMS analyses and a research visit to BGC was funded by NZARI (grant 2017-1-3). Antarctic Science Bursary provided funding for a research visit to Durham University. Andrew Mackintosh was supported by ARC SRIEAS grant SR200100005, Securing Antarctica?s Environmental Future
Publisher Copyright:
© Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License..All right reserved.
PY - 2021/12/7
Y1 - 2021/12/7
N2 - 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 2ĝm/yr during the mid-Holocene (ĝ1/4ĝ6.5ĝka). Thinning slowed at 6ĝka, 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 4-7ĝkyr 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 ĝ1/4ĝ2000-year period of dynamic glacier thinning in the recent geological past.
AB - 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 2ĝm/yr during the mid-Holocene (ĝ1/4ĝ6.5ĝka). Thinning slowed at 6ĝka, 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 4-7ĝkyr 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 ĝ1/4ĝ2000-year period of dynamic glacier thinning in the recent geological past.
UR - https://www.scopus.com/pages/publications/85121235835
U2 - 10.5194/tc-15-5447-2021
DO - 10.5194/tc-15-5447-2021
M3 - Article
AN - SCOPUS:85121235835
SN - 1994-0416
VL - 15
SP - 5447
EP - 5471
JO - The Cryosphere
JF - The Cryosphere
IS - 12
ER -
SDG 14 Life Below Water
SDG 15 Life on Land