Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation
Ongoing retreat of Antarctica’s marine-based glaciers is associated with warm (~2° C) modified Circumpolar Deep Water intrusion onto the continental shelf, suggesting that Southern Ocean temperatures may influence Antarctic ice sheet stability. Understanding past cryosphere response to environmental...
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ftunisfloridatam:oai:digitalcommons.usf.edu:etd-7153 2023-06-11T04:03:27+02:00 Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation Guitard, Michelle 2015-10-19T07:00:00Z application/pdf https://digitalcommons.usf.edu/etd/5957 https://digitalcommons.usf.edu/context/etd/article/7153/viewcontent/Guitard_usf_0206M_13154.pdf unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/etd/5957 https://digitalcommons.usf.edu/context/etd/article/7153/viewcontent/Guitard_usf_0206M_13154.pdf default USF Tampa Graduate Theses and Dissertations Amery Ice Shelf radiocarbon cosmogenic beryllium-10 millennial-scale variability Geology thesis 2015 ftunisfloridatam 2023-05-04T18:05:37Z Ongoing retreat of Antarctica’s marine-based glaciers is associated with warm (~2° C) modified Circumpolar Deep Water intrusion onto the continental shelf, suggesting that Southern Ocean temperatures may influence Antarctic ice sheet stability. Understanding past cryosphere response to environmental forcing is crucial to modeling future ice sheet behavior. Of particular interest is the response of the East Antarctic Ice Sheet (EAIS), which stands to contribute ~20 m to global sea level. However, marine sediment sequences recording timing and variability of EAIS fluctuations through the last major climate shift, the Last Glacial Maximum (LGM), are either missing from the margin or have poor chronological control. Here we present three marine sediment cores that contain a record of pre-LGM fluctuations of the marine-based Lambert Glacier-Amery Ice Shelf (LG-AIS) system into Prydz Channel, East Antarctica. Analyses of core lithology, physical properties, cosmogenic nuclide concentration and diatom assemblage demonstrate that Prydz Channel was characterized by alternating open-marine and sub-shelf deposition, implying repeated LG-AIS fluctuations through the LGM. Our radiocarbon chronology demonstrates that LG-AIS fluctuations occurred on millennial timescales. Our record corroborates regional marine and terrestrial records, which demonstrate millennial scale variability in Antarctic Circumpolar Current strength, ice-rafted debris deposition, sea ice extent, Antarctic atmospheric temperature, and Southern Ocean sea surface temperature. This evidence suggests that the EAIS was sensitive to sub-orbital climate forcing in the past, and has implications for modeling future EAIS behavior. Thesis Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Lambert Glacier Sea ice Southern Ocean Digital Commons University of South Florida (USF) Antarctic Southern Ocean East Antarctica East Antarctic Ice Sheet Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Lambert Glacier ENVELOPE(67.490,67.490,-73.065,-73.065) Prydz Channel ENVELOPE(73.000,73.000,-67.000,-67.000) |
institution |
Open Polar |
collection |
Digital Commons University of South Florida (USF) |
op_collection_id |
ftunisfloridatam |
language |
unknown |
topic |
Amery Ice Shelf radiocarbon cosmogenic beryllium-10 millennial-scale variability Geology |
spellingShingle |
Amery Ice Shelf radiocarbon cosmogenic beryllium-10 millennial-scale variability Geology Guitard, Michelle Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
topic_facet |
Amery Ice Shelf radiocarbon cosmogenic beryllium-10 millennial-scale variability Geology |
description |
Ongoing retreat of Antarctica’s marine-based glaciers is associated with warm (~2° C) modified Circumpolar Deep Water intrusion onto the continental shelf, suggesting that Southern Ocean temperatures may influence Antarctic ice sheet stability. Understanding past cryosphere response to environmental forcing is crucial to modeling future ice sheet behavior. Of particular interest is the response of the East Antarctic Ice Sheet (EAIS), which stands to contribute ~20 m to global sea level. However, marine sediment sequences recording timing and variability of EAIS fluctuations through the last major climate shift, the Last Glacial Maximum (LGM), are either missing from the margin or have poor chronological control. Here we present three marine sediment cores that contain a record of pre-LGM fluctuations of the marine-based Lambert Glacier-Amery Ice Shelf (LG-AIS) system into Prydz Channel, East Antarctica. Analyses of core lithology, physical properties, cosmogenic nuclide concentration and diatom assemblage demonstrate that Prydz Channel was characterized by alternating open-marine and sub-shelf deposition, implying repeated LG-AIS fluctuations through the LGM. Our radiocarbon chronology demonstrates that LG-AIS fluctuations occurred on millennial timescales. Our record corroborates regional marine and terrestrial records, which demonstrate millennial scale variability in Antarctic Circumpolar Current strength, ice-rafted debris deposition, sea ice extent, Antarctic atmospheric temperature, and Southern Ocean sea surface temperature. This evidence suggests that the EAIS was sensitive to sub-orbital climate forcing in the past, and has implications for modeling future EAIS behavior. |
format |
Thesis |
author |
Guitard, Michelle |
author_facet |
Guitard, Michelle |
author_sort |
Guitard, Michelle |
title |
Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
title_short |
Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
title_full |
Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
title_fullStr |
Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
title_full_unstemmed |
Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation |
title_sort |
millennial-scale variability of a major east antarctic outlet glacier during the last glaciation |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2015 |
url |
https://digitalcommons.usf.edu/etd/5957 https://digitalcommons.usf.edu/context/etd/article/7153/viewcontent/Guitard_usf_0206M_13154.pdf |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) ENVELOPE(67.490,67.490,-73.065,-73.065) ENVELOPE(73.000,73.000,-67.000,-67.000) |
geographic |
Antarctic Southern Ocean East Antarctica East Antarctic Ice Sheet Amery Amery Ice Shelf Lambert Glacier Prydz Channel |
geographic_facet |
Antarctic Southern Ocean East Antarctica East Antarctic Ice Sheet Amery Amery Ice Shelf Lambert Glacier Prydz Channel |
genre |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Lambert Glacier Sea ice Southern Ocean |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Lambert Glacier Sea ice Southern Ocean |
op_source |
USF Tampa Graduate Theses and Dissertations |
op_relation |
https://digitalcommons.usf.edu/etd/5957 https://digitalcommons.usf.edu/context/etd/article/7153/viewcontent/Guitard_usf_0206M_13154.pdf |
op_rights |
default |
_version_ |
1768379698254970880 |