Reconciling persistent sub-zero temperatures in the McMurdo dry valleys, Antarctica, with Neogene dynamic marine ice-sheet fluctuations

In the Ross Sea sector of Antarctica, periodic large-scale marine ice-sheet fluctuations since the mid-Miocene are recorded by drill core and seismic data, revealing a dynamic ice-sheet response to past increases in temperature and atmospheric CO2. In the adjacent, predominantly ice-free McMurdo Dry...

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Bibliographic Details
Published in:Geology (Boulder) 2022-05, Vol.50 (5), p.557-561
Main Authors: Halberstadt, Anna Ruth W, Kowalewski, Douglas E, DeConto, Robert M
Format: Article
Language:English
Subjects:
ANDRILL
Antarctic ice sheet
Antarctica
Atmospheric models
Carbon dioxide
Cenozoic
Climate
Climate change
climate effects
Climate models
Cold
cores
Coring
Cryopreservation
East Antarctic ice sheet
Fluctuations
Freezing
Geology
geophysical methods
glacial environment
glacial geology
Glaciation
Global warming
Ice
Ice sheets
ice shelves
Landscape preservation
marine environment
McMurdo dry valleys
Miocene
Neogene
paleoclimatology
paleogeography
paleotemperature
Polar environments
Regional climate models
Regional climates
Ross Sea
Seismic data
seismic methods
Seismic stability
Seismological data
Southern Ocean
Stratigraphy
Surface temperature
Terrestrial environments
Tertiary
Valleys
Victoria Land
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Summary:In the Ross Sea sector of Antarctica, periodic large-scale marine ice-sheet fluctuations since the mid-Miocene are recorded by drill core and seismic data, revealing a dynamic ice-sheet response to past increases in temperature and atmospheric CO2. In the adjacent, predominantly ice-free McMurdo Dry Valleys (MDVs), preserved terrestrial landscapes reflect persistent cold conditions and have been interpreted as indicators of a stable polar ice sheet, implying that the Antarctic Ice Sheet was largely insensitive during past warm periods. These disparate data-based perspectives highlight a long-standing debate around the past stability of the Antarctic Ice Sheet, with direct implications for the future ice-sheet response to ongoing climate warming. We reconcile marine records of dynamic ice-sheet behavior and episodic open-marine conditions with nearby ancient terrestrial landscapes recording consistent cold-polar conditions. Coupled ice-sheet and regional climate models nested at a high resolution are used to investigate surface temperatures in the MDVs during past warm periods. We find that high-elevation regions of the MDVs remain below freezing even when ice-free conditions prevail in the nearby Ross Sea. We compare observed landscapes with the spatial extent of modeled persistent cold conditions required for preservation of these ancient features, demonstrating that frozen MDVs landscapes could have coexisted with receded or collapsed ice sheets during past warm periods.
ISSN:0091-7613
1943-2682
DOI:10.1130/G49664.1