Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial
Present-day low-latitude eastern and western Atlantic basins are geochemically distinct below the sill depth of the Mid-Atlantic Ridge. While Antarctic Bottom Water (AABW) circulates freely in the western Atlantic, flow into the eastern Atlantic is restricted below 4 km which results in filling the...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.692007 2023-05-15T13:42:09+02:00 Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial Beveridge, N Elderfield, Henry Shackleton, Nicholas J MEDIAN LATITUDE: 21.474670 * MEDIAN LONGITUDE: -20.578937 * SOUTH-BOUND LATITUDE: 18.997900 * WEST-BOUND LONGITUDE: -22.762000 * NORTH-BOUND LATITUDE: 24.615000 * EAST-BOUND LONGITUDE: -18.573333 * DATE/TIME START: 1971-11-08T00:00:00 * DATE/TIME END: 1990-10-17T00:00:00 1995-04-30 application/zip, 10 datasets https://doi.pangaea.de/10.1594/PANGAEA.692007 https://doi.org/10.1594/PANGAEA.692007 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.692007 https://doi.org/10.1594/PANGAEA.692007 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Beveridge, N; Elderfield, Henry; Shackleton, Nicholas J (1995): Deep thermohaline circulation in the low-latitude Atlantic during the last glacial. Paleoceanography, 10(3), 643-660, https://doi.org/10.1029/94PA03353 Biogeochemical Ocean Flux Study BOFS BOFS26/6K BOFS26#6 BOFS28/3K BOFS28#3 BOFS29/1K BOFS29#1 BOFS30/3K BOFS30#3 BOFS31/1K BOFS31#1 CD53 Charles Darwin East Atlantic GIK12328-5 JGOFS Joint Global Ocean Flux Study KAL Kasten corer M25 Meteor (1964) Northeast Atlantic Dataset 1995 ftpangaea https://doi.org/10.1594/PANGAEA.692007 https://doi.org/10.1029/94PA03353 2023-01-20T07:31:09Z Present-day low-latitude eastern and western Atlantic basins are geochemically distinct below the sill depth of the Mid-Atlantic Ridge. While Antarctic Bottom Water (AABW) circulates freely in the western Atlantic, flow into the eastern Atlantic is restricted below 4 km which results in filling the abyssal depths of this basin with water of geochemical similarity to nutrient depleted North Atlantic Deep Water. Using carbon isotopes and Cd/Ca ratios in benthic foraminifera we reconstruct the geochemistry of these basins during the last glacial maximum. Results indicate that deep eastern and western Atlantic basins became geochemically identical during the last glacial. This was achieved by shoaling of the upper surface of AABW above the sill depth of the Mid-Atlantic Ridge, which allowed bottom waters in both basins to be filled with the same water mass. Although AABW became the dominant water mass in the deep eastern Atlantic basin during the glacial, Holocene-glacial delta13C-PO4 shifts in this basin are in Redfield proportions, unlike the disproportionate Holocene-glacial delta13C-PO4 shifts observed in the Southern Ocean. By examining the composition of deep and intermediate waters throughout the Atlantic, we show that this effect was induced by a change in gradient of the delta13C-PO4 deepwater mixing line during glacial times. Evidence from high-latitude planktonic data suggests that the change in gradient of the deepwater mixing line was brought about through a significant reduction in the thermodynamic effect on Southern Ocean surface waters. By using coupled delta13C-PO4 data to constrain the composition of end member water masses in the glacial Atlantic, we conclude that deep waters in the low-latitude glacial Atlantic were composed of a mixture of northern and southern source waters in a ratio of 1:3. Dataset Antarc* Antarctic North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean PANGAEA - Data Publisher for Earth & Environmental Science Antarctic Southern Ocean Mid-Atlantic Ridge ENVELOPE(-22.762000,-18.573333,24.615000,18.997900) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Biogeochemical Ocean Flux Study BOFS BOFS26/6K BOFS26#6 BOFS28/3K BOFS28#3 BOFS29/1K BOFS29#1 BOFS30/3K BOFS30#3 BOFS31/1K BOFS31#1 CD53 Charles Darwin East Atlantic GIK12328-5 JGOFS Joint Global Ocean Flux Study KAL Kasten corer M25 Meteor (1964) Northeast Atlantic |
spellingShingle |
Biogeochemical Ocean Flux Study BOFS BOFS26/6K BOFS26#6 BOFS28/3K BOFS28#3 BOFS29/1K BOFS29#1 BOFS30/3K BOFS30#3 BOFS31/1K BOFS31#1 CD53 Charles Darwin East Atlantic GIK12328-5 JGOFS Joint Global Ocean Flux Study KAL Kasten corer M25 Meteor (1964) Northeast Atlantic Beveridge, N Elderfield, Henry Shackleton, Nicholas J Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
topic_facet |
Biogeochemical Ocean Flux Study BOFS BOFS26/6K BOFS26#6 BOFS28/3K BOFS28#3 BOFS29/1K BOFS29#1 BOFS30/3K BOFS30#3 BOFS31/1K BOFS31#1 CD53 Charles Darwin East Atlantic GIK12328-5 JGOFS Joint Global Ocean Flux Study KAL Kasten corer M25 Meteor (1964) Northeast Atlantic |
description |
Present-day low-latitude eastern and western Atlantic basins are geochemically distinct below the sill depth of the Mid-Atlantic Ridge. While Antarctic Bottom Water (AABW) circulates freely in the western Atlantic, flow into the eastern Atlantic is restricted below 4 km which results in filling the abyssal depths of this basin with water of geochemical similarity to nutrient depleted North Atlantic Deep Water. Using carbon isotopes and Cd/Ca ratios in benthic foraminifera we reconstruct the geochemistry of these basins during the last glacial maximum. Results indicate that deep eastern and western Atlantic basins became geochemically identical during the last glacial. This was achieved by shoaling of the upper surface of AABW above the sill depth of the Mid-Atlantic Ridge, which allowed bottom waters in both basins to be filled with the same water mass. Although AABW became the dominant water mass in the deep eastern Atlantic basin during the glacial, Holocene-glacial delta13C-PO4 shifts in this basin are in Redfield proportions, unlike the disproportionate Holocene-glacial delta13C-PO4 shifts observed in the Southern Ocean. By examining the composition of deep and intermediate waters throughout the Atlantic, we show that this effect was induced by a change in gradient of the delta13C-PO4 deepwater mixing line during glacial times. Evidence from high-latitude planktonic data suggests that the change in gradient of the deepwater mixing line was brought about through a significant reduction in the thermodynamic effect on Southern Ocean surface waters. By using coupled delta13C-PO4 data to constrain the composition of end member water masses in the glacial Atlantic, we conclude that deep waters in the low-latitude glacial Atlantic were composed of a mixture of northern and southern source waters in a ratio of 1:3. |
format |
Dataset |
author |
Beveridge, N Elderfield, Henry Shackleton, Nicholas J |
author_facet |
Beveridge, N Elderfield, Henry Shackleton, Nicholas J |
author_sort |
Beveridge, N |
title |
Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
title_short |
Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
title_full |
Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
title_fullStr |
Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
title_full_unstemmed |
Deep thermohaline Circulation in the low-latitude Atlantic during the Last Glacial |
title_sort |
deep thermohaline circulation in the low-latitude atlantic during the last glacial |
publisher |
PANGAEA |
publishDate |
1995 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.692007 https://doi.org/10.1594/PANGAEA.692007 |
op_coverage |
MEDIAN LATITUDE: 21.474670 * MEDIAN LONGITUDE: -20.578937 * SOUTH-BOUND LATITUDE: 18.997900 * WEST-BOUND LONGITUDE: -22.762000 * NORTH-BOUND LATITUDE: 24.615000 * EAST-BOUND LONGITUDE: -18.573333 * DATE/TIME START: 1971-11-08T00:00:00 * DATE/TIME END: 1990-10-17T00:00:00 |
long_lat |
ENVELOPE(-22.762000,-18.573333,24.615000,18.997900) |
geographic |
Antarctic Southern Ocean Mid-Atlantic Ridge |
geographic_facet |
Antarctic Southern Ocean Mid-Atlantic Ridge |
genre |
Antarc* Antarctic North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean |
op_source |
Supplement to: Beveridge, N; Elderfield, Henry; Shackleton, Nicholas J (1995): Deep thermohaline circulation in the low-latitude Atlantic during the last glacial. Paleoceanography, 10(3), 643-660, https://doi.org/10.1029/94PA03353 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.692007 https://doi.org/10.1594/PANGAEA.692007 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.692007 https://doi.org/10.1029/94PA03353 |
_version_ |
1766163324950544384 |