Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica
Modeling studies and field mapping show that increases in ice thickness during glacial periods were not uniform across Antarctica. Rather, outlet glaciers that flow through the Transantarctic Mountains (TAM) experienced the greatest changes in ice thickness. As a result, ice-free areas that are curr...
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ftcopernicus:oai:publications.copernicus.org:esurfd86244 2023-05-15T13:55:28+02:00 Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica Diaz, Melisa A. Corbett, Lee B. Bierman, Paul R. Adams, Byron J. Wall, Diana H. Hogg, Ian D. Fierer, Noah Lyons, W. Berry 2020-07-08 application/pdf https://doi.org/10.5194/esurf-2020-50 https://esurf.copernicus.org/preprints/esurf-2020-50/ eng eng doi:10.5194/esurf-2020-50 https://esurf.copernicus.org/preprints/esurf-2020-50/ eISSN: 2196-632X Text 2020 ftcopernicus https://doi.org/10.5194/esurf-2020-50 2020-07-20T16:22:02Z Modeling studies and field mapping show that increases in ice thickness during glacial periods were not uniform across Antarctica. Rather, outlet glaciers that flow through the Transantarctic Mountains (TAM) experienced the greatest changes in ice thickness. As a result, ice-free areas that are currently exposed may have been covered by ice at various points during the Cenozoic, thereby providing a record of past ice sheet behavior. We collected soil surface samples and depth profiles every 5 cm to refusal (up to 30 cm) from eleven ice-free areas along the Shackleton Glacier, a major outlet glacier of the East Antarctic Ice Sheet (EAIS) and measured meteoric 10 Be and NO 3 − concentrations to calculate and estimate surface exposure ages. Using 10 Be inventories from three locations, calculated maximum exposure ages range from 4.1 Myr at Roberts Massif near the Polar Plateau to 0.11 Myr at Bennett Platform further north. When corrected for inheritance of 10 Be from prior exposure, the ages (representing a minimum) range from 0.14 Myr at Roberts Massif to 0.04 Myr at Thanksgiving Valley. We correlate NO 3 − concentrations with meteoric 10 Be to estimate exposure ages for all locations with NO 3 − depth profiles but only surface 10 Be data. These results indicate that NO 3 − concentrations can be used in conjunction with meteoric 10 Be to help interpret EAIS dynamics over time. We show that the Shackleton Glacier has the greatest fluctuations near the Ross Ice Shelf while tributary glaciers are more stable, reflecting the sensitivity of the EAIS to climate shifts at TAM margins. Text Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Shackleton Glacier Copernicus Publications: E-Journals Antarctic Bennett Platform ENVELOPE(-177.833,-177.833,-85.217,-85.217) East Antarctic Ice Sheet Polar Plateau ENVELOPE(0.000,0.000,-90.000,-90.000) Roberts massif ENVELOPE(-177.083,-177.083,-85.533,-85.533) Ross Ice Shelf Shackleton Shackleton Glacier ENVELOPE(-37.200,-37.200,-54.133,-54.133) Transantarctic Mountains |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Modeling studies and field mapping show that increases in ice thickness during glacial periods were not uniform across Antarctica. Rather, outlet glaciers that flow through the Transantarctic Mountains (TAM) experienced the greatest changes in ice thickness. As a result, ice-free areas that are currently exposed may have been covered by ice at various points during the Cenozoic, thereby providing a record of past ice sheet behavior. We collected soil surface samples and depth profiles every 5 cm to refusal (up to 30 cm) from eleven ice-free areas along the Shackleton Glacier, a major outlet glacier of the East Antarctic Ice Sheet (EAIS) and measured meteoric 10 Be and NO 3 − concentrations to calculate and estimate surface exposure ages. Using 10 Be inventories from three locations, calculated maximum exposure ages range from 4.1 Myr at Roberts Massif near the Polar Plateau to 0.11 Myr at Bennett Platform further north. When corrected for inheritance of 10 Be from prior exposure, the ages (representing a minimum) range from 0.14 Myr at Roberts Massif to 0.04 Myr at Thanksgiving Valley. We correlate NO 3 − concentrations with meteoric 10 Be to estimate exposure ages for all locations with NO 3 − depth profiles but only surface 10 Be data. These results indicate that NO 3 − concentrations can be used in conjunction with meteoric 10 Be to help interpret EAIS dynamics over time. We show that the Shackleton Glacier has the greatest fluctuations near the Ross Ice Shelf while tributary glaciers are more stable, reflecting the sensitivity of the EAIS to climate shifts at TAM margins. |
format |
Text |
author |
Diaz, Melisa A. Corbett, Lee B. Bierman, Paul R. Adams, Byron J. Wall, Diana H. Hogg, Ian D. Fierer, Noah Lyons, W. Berry |
spellingShingle |
Diaz, Melisa A. Corbett, Lee B. Bierman, Paul R. Adams, Byron J. Wall, Diana H. Hogg, Ian D. Fierer, Noah Lyons, W. Berry Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
author_facet |
Diaz, Melisa A. Corbett, Lee B. Bierman, Paul R. Adams, Byron J. Wall, Diana H. Hogg, Ian D. Fierer, Noah Lyons, W. Berry |
author_sort |
Diaz, Melisa A. |
title |
Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
title_short |
Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
title_full |
Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
title_fullStr |
Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
title_full_unstemmed |
Relative terrestrial exposure ages inferred from meteoric 10Be and NO3− concentrations in soils along the Shackleton Glacier, Antarctica |
title_sort |
relative terrestrial exposure ages inferred from meteoric 10be and no3− concentrations in soils along the shackleton glacier, antarctica |
publishDate |
2020 |
url |
https://doi.org/10.5194/esurf-2020-50 https://esurf.copernicus.org/preprints/esurf-2020-50/ |
long_lat |
ENVELOPE(-177.833,-177.833,-85.217,-85.217) ENVELOPE(0.000,0.000,-90.000,-90.000) ENVELOPE(-177.083,-177.083,-85.533,-85.533) ENVELOPE(-37.200,-37.200,-54.133,-54.133) |
geographic |
Antarctic Bennett Platform East Antarctic Ice Sheet Polar Plateau Roberts massif Ross Ice Shelf Shackleton Shackleton Glacier Transantarctic Mountains |
geographic_facet |
Antarctic Bennett Platform East Antarctic Ice Sheet Polar Plateau Roberts massif Ross Ice Shelf Shackleton Shackleton Glacier Transantarctic Mountains |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Shackleton Glacier |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Shackleton Glacier |
op_source |
eISSN: 2196-632X |
op_relation |
doi:10.5194/esurf-2020-50 https://esurf.copernicus.org/preprints/esurf-2020-50/ |
op_doi |
https://doi.org/10.5194/esurf-2020-50 |
_version_ |
1766262083915087872 |