Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic
We present a high-resolution paleoceanographic record of deglaciation based on diatom assemblages from a core located just south of the Polar Front in the southwest Atlantic. Core KC073 is from a sediment drift at the mouth of the Falkland Trough and contains sediments from the Last Glacial Maximum...
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Language: | English |
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American Geophysical Union
2005
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Online Access: | https://orca.cardiff.ac.uk/id/eprint/1297/ https://doi.org/10.1029/2004PA001055 https://orca.cardiff.ac.uk/id/eprint/1297/1/ALLEN__Orca_1297.pdf |
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:1297 2023-05-15T13:39:21+02:00 Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic Allen, Claire S. Pike, Jennifer Pudsey, Carol J. Leventer, Amy 2005-06-01 application/pdf https://orca.cardiff.ac.uk/id/eprint/1297/ https://doi.org/10.1029/2004PA001055 https://orca.cardiff.ac.uk/id/eprint/1297/1/ALLEN__Orca_1297.pdf en eng American Geophysical Union https://orca.cardiff.ac.uk/id/eprint/1297/1/ALLEN__Orca_1297.pdf Allen, Claire S., Pike, Jennifer https://orca.cardiff.ac.uk/view/cardiffauthors/A0179070.html orcid:0000-0001-9415-6003 orcid:0000-0001-9415-6003, Pudsey, Carol J. and Leventer, Amy 2005. Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic. Paleoceanography 20 (2) , PA2012. 10.1029/2004PA001055 https://doi.org/10.1029/2004PA001055 file https://orca.cardiff.ac.uk/1297/1/ALLEN__Orca_1297.pdf doi:10.1029/2004PA001055 GC Oceanography QE Geology Article PeerReviewed 2005 ftunivcardiff https://doi.org/10.1029/2004PA001055 2022-10-20T22:31:53Z We present a high-resolution paleoceanographic record of deglaciation based on diatom assemblages from a core located just south of the Polar Front in the southwest Atlantic. Core KC073 is from a sediment drift at the mouth of the Falkland Trough and contains sediments from the Last Glacial Maximum (LGM) to present, dated using radiocarbon dates on bulk organic matter and radiolarian stratigraphy. The site lies along the path of the Antarctic Circumpolar Current (ACC) and immediately downstream of where North Atlantic Deep Water (NADW) is entrained into the ACC. Significant variations in ocean conditions are reflected in high-amplitude changes in diatom concentrations and assemblage composition. The diatom assemblage at the LGM indicates that winter sea ice extent was at least 5° farther north than present until at least 19.0 ka (calendar years) and summer sea ice may have occasionally extended over the site, but for the most part it lay to the south. During deglaciation, Chaetoceros resting spores (CRS) dominate the diatom assemblage with valve concentrations in excess of 500 × 106 valves per gram. Submillennial-scale variations in the numbers of CRS and Thalassiosira antarctica occur throughout the late deglacial and dominate the changes in diatom concentration. We propose that the influx of CRS is controlled by the flow of NADW over the Falkland Plateau. As such our data provide unique evidence that NADW impacted on this sector of the Southern Ocean during deglaciation. During the Holocene the sedimentation rate dramatically reduced. We suggest that the ACC flow increased over the site and inhibited settling and winnowed the surface sediments. Article in Journal/Newspaper Antarc* Antarctic Antarctica NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean Cardiff University: ORCA (Online Research @ Cardiff) Antarctic Falkland Plateau ENVELOPE(-50.000,-50.000,-51.000,-51.000) Falkland Trough ENVELOPE(-49.750,-49.750,-52.750,-52.750) Southern Ocean The Antarctic Paleoceanography 20 2 n/a n/a |
institution |
Open Polar |
collection |
Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
topic |
GC Oceanography QE Geology |
spellingShingle |
GC Oceanography QE Geology Allen, Claire S. Pike, Jennifer Pudsey, Carol J. Leventer, Amy Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
topic_facet |
GC Oceanography QE Geology |
description |
We present a high-resolution paleoceanographic record of deglaciation based on diatom assemblages from a core located just south of the Polar Front in the southwest Atlantic. Core KC073 is from a sediment drift at the mouth of the Falkland Trough and contains sediments from the Last Glacial Maximum (LGM) to present, dated using radiocarbon dates on bulk organic matter and radiolarian stratigraphy. The site lies along the path of the Antarctic Circumpolar Current (ACC) and immediately downstream of where North Atlantic Deep Water (NADW) is entrained into the ACC. Significant variations in ocean conditions are reflected in high-amplitude changes in diatom concentrations and assemblage composition. The diatom assemblage at the LGM indicates that winter sea ice extent was at least 5° farther north than present until at least 19.0 ka (calendar years) and summer sea ice may have occasionally extended over the site, but for the most part it lay to the south. During deglaciation, Chaetoceros resting spores (CRS) dominate the diatom assemblage with valve concentrations in excess of 500 × 106 valves per gram. Submillennial-scale variations in the numbers of CRS and Thalassiosira antarctica occur throughout the late deglacial and dominate the changes in diatom concentration. We propose that the influx of CRS is controlled by the flow of NADW over the Falkland Plateau. As such our data provide unique evidence that NADW impacted on this sector of the Southern Ocean during deglaciation. During the Holocene the sedimentation rate dramatically reduced. We suggest that the ACC flow increased over the site and inhibited settling and winnowed the surface sediments. |
format |
Article in Journal/Newspaper |
author |
Allen, Claire S. Pike, Jennifer Pudsey, Carol J. Leventer, Amy |
author_facet |
Allen, Claire S. Pike, Jennifer Pudsey, Carol J. Leventer, Amy |
author_sort |
Allen, Claire S. |
title |
Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
title_short |
Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
title_full |
Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
title_fullStr |
Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
title_full_unstemmed |
Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic |
title_sort |
submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest atlantic |
publisher |
American Geophysical Union |
publishDate |
2005 |
url |
https://orca.cardiff.ac.uk/id/eprint/1297/ https://doi.org/10.1029/2004PA001055 https://orca.cardiff.ac.uk/id/eprint/1297/1/ALLEN__Orca_1297.pdf |
long_lat |
ENVELOPE(-50.000,-50.000,-51.000,-51.000) ENVELOPE(-49.750,-49.750,-52.750,-52.750) |
geographic |
Antarctic Falkland Plateau Falkland Trough Southern Ocean The Antarctic |
geographic_facet |
Antarctic Falkland Plateau Falkland Trough Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctica NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/1297/1/ALLEN__Orca_1297.pdf Allen, Claire S., Pike, Jennifer https://orca.cardiff.ac.uk/view/cardiffauthors/A0179070.html orcid:0000-0001-9415-6003 orcid:0000-0001-9415-6003, Pudsey, Carol J. and Leventer, Amy 2005. Submillenial variations in ocean conditions during deglaciation based on diatom assemblages from the southwest Atlantic. Paleoceanography 20 (2) , PA2012. 10.1029/2004PA001055 https://doi.org/10.1029/2004PA001055 file https://orca.cardiff.ac.uk/1297/1/ALLEN__Orca_1297.pdf doi:10.1029/2004PA001055 |
op_doi |
https://doi.org/10.1029/2004PA001055 |
container_title |
Paleoceanography |
container_volume |
20 |
container_issue |
2 |
container_start_page |
n/a |
op_container_end_page |
n/a |
_version_ |
1766117652095303680 |