Holocene Accumulation and Ice Flow near the West Antarctic Ice Sheet Divide Ice Core Site

The West Antarctic Ice Sheet Divide Core (WDC) provided a high-resolution climate record from near the Ross-Amundsen Divide in Central West Antarctica. In addition, radar-detected internal layers in the vicinity of the WDC site have been dated directly from the ice core to provide spatial variations...

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Bibliographic Details
Published in:Journal of geophysical research. Earth surface 2016-05, Vol.121 (5), p.907-924
Main Authors: Koutnik, Michelle R., Fudge, T.J., Conway, Howard, Waddington, Edwin D., Neumann, Thomas A., Cuffey, Kurt M., Buizert, Christo, Taylor, Kendrick C.
Format: Article
Language:English
Subjects:
Accumulation
Antarctica
Brackish
Climate
Earth surface
Geophysics
Glaciers
Holocene
Ice
ice flow
Ice sheets
Marine
Meteorology And Climatology
Radar
Sea level
Time
Upstream
West Antarctica
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Summary:The West Antarctic Ice Sheet Divide Core (WDC) provided a high-resolution climate record from near the Ross-Amundsen Divide in Central West Antarctica. In addition, radar-detected internal layers in the vicinity of the WDC site have been dated directly from the ice core to provide spatial variations in the age structure of the region. Using these two data sets together, we first infer a high-resolution Holocene accumulation-rate history from 9.2 thousand years of the ice-core timescale and then confirm that this climate history is consistent with internal layers upstream of the core site. Even though the WDC was drilled only 24 kilometers from the modern ice divide, advection of ice from upstream must be taken into account. We evaluate histories of accumulation rate by using a flowband model to generate internal layers that we compare to observed layers. Results show that the centennially averaged accumulation rate was over 20 percent lower than modern at 9.2 thousand years before present (B.P.), increased by 40 percent from 9.2 to 2.3 thousand years B.P., and decreased by at least 10 percent over the past 2 thousand years B.P. to the modern values; these Holocene accumulation-rate changes in Central West Antarctica are larger than changes inferred from East Antarctic ice-core records. Despite significant changes in accumulation rate, throughout the Holocene the regional accumulation pattern has likely remained similar to today, and the ice-divide position has likely remained on average within 5 kilometers of its modern position. Continent-scale ice-sheet models used for reconstructions of West Antarctic ice volume should incorporate this accumulation history.
ISSN:2169-9003
2169-9011
DOI:10.1002/2015JF003668