Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds
We developed a new method to calculate sea surface salinities (SSS) and densities (SSD) from planktonic foraminiferal delta(18)O and sea surface temperatures (SST) as determined from planktonic foraminiferal species abundances. SST, SSS, and SSD records were calculated for the last 45,000 years for...
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1995
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ftucl:oai:eprints.ucl.ac.uk.OAI2:170786 2024-10-13T14:07:10+00:00 Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds Maslin, MA Shackleton, NJ Pflaumann, U 1995-06 application/pdf https://discovery.ucl.ac.uk/id/eprint/170786/1/94PA03040.pdf https://discovery.ucl.ac.uk/id/eprint/170786/ eng eng AMER GEOPHYSICAL UNION https://discovery.ucl.ac.uk/id/eprint/170786/1/94PA03040.pdf https://discovery.ucl.ac.uk/id/eprint/170786/ open Paleoceanography , 10 (3) 527 - 544. (1995) Foraminifer Neogloboquadrina-pachyderma U-Th ages Sea-level Meltwater discharge Mass-spectrometry Labrador sea Ice-sheet Deglaciation Ocean Sediments Article 1995 ftucl 2024-09-30T07:42:09Z We developed a new method to calculate sea surface salinities (SSS) and densities (SSD) from planktonic foraminiferal delta(18)O and sea surface temperatures (SST) as determined from planktonic foraminiferal species abundances. SST, SSS, and SSD records were calculated for the last 45,000 years for Biogeochemical Oceanic Flux Study (BOFS) cores 5K and 8K recovered from the northeast Atlantic. The strongest feature is the dramatic drop in all three parameters during the Heinrich ''ice-rafting'' events. We modelled the possibility of deepwater formation in the northeast Atlantic from the SSD records, by assuming that the surface waters at our sites cooled as they flowed further north. Comparison with modelled North Atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45,000 and 30,000 C-14 years B.P. (interrupted by iceberg meltwater input of Heinrich event 3 and 4, at 27,000 and 38,000 C-14 years B.P.) and during the Holocene. No amount of cooling in the northeast Atlantic between 30,000 and 13,000 years could cause deep water to form, because of the low salinities resulting from the high meltwater inputs from icebergs. Our records indicate that after each Heinrich event there were periods of climatic rebound, with milder conditions persisting for up to 2000 years, as indicated by the presence of warmer and more saline water masses. After these warm periods conditions returned to average glacial levels. These short term cold and warm episodes in the northeast Atlantic ate superimposed on the general trend towards colder conditions of the Last Glacial Maximum (LGM). Heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the Fennoscandian ice sheet. We propose that meltwater input of Heinrich event 1 significantly reduced North Atlantic Deep Water formation reducing the heat exchange between the low and high latitudes, thus delaying deglaciation by about 1500 radiocarbon years (2000 calendar years). Article in Journal/Newspaper Fennoscandian Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic Northeast Atlantic Sea ice University College London: UCL Discovery |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Foraminifer Neogloboquadrina-pachyderma U-Th ages Sea-level Meltwater discharge Mass-spectrometry Labrador sea Ice-sheet Deglaciation Ocean Sediments |
spellingShingle |
Foraminifer Neogloboquadrina-pachyderma U-Th ages Sea-level Meltwater discharge Mass-spectrometry Labrador sea Ice-sheet Deglaciation Ocean Sediments Maslin, MA Shackleton, NJ Pflaumann, U Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
topic_facet |
Foraminifer Neogloboquadrina-pachyderma U-Th ages Sea-level Meltwater discharge Mass-spectrometry Labrador sea Ice-sheet Deglaciation Ocean Sediments |
description |
We developed a new method to calculate sea surface salinities (SSS) and densities (SSD) from planktonic foraminiferal delta(18)O and sea surface temperatures (SST) as determined from planktonic foraminiferal species abundances. SST, SSS, and SSD records were calculated for the last 45,000 years for Biogeochemical Oceanic Flux Study (BOFS) cores 5K and 8K recovered from the northeast Atlantic. The strongest feature is the dramatic drop in all three parameters during the Heinrich ''ice-rafting'' events. We modelled the possibility of deepwater formation in the northeast Atlantic from the SSD records, by assuming that the surface waters at our sites cooled as they flowed further north. Comparison with modelled North Atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45,000 and 30,000 C-14 years B.P. (interrupted by iceberg meltwater input of Heinrich event 3 and 4, at 27,000 and 38,000 C-14 years B.P.) and during the Holocene. No amount of cooling in the northeast Atlantic between 30,000 and 13,000 years could cause deep water to form, because of the low salinities resulting from the high meltwater inputs from icebergs. Our records indicate that after each Heinrich event there were periods of climatic rebound, with milder conditions persisting for up to 2000 years, as indicated by the presence of warmer and more saline water masses. After these warm periods conditions returned to average glacial levels. These short term cold and warm episodes in the northeast Atlantic ate superimposed on the general trend towards colder conditions of the Last Glacial Maximum (LGM). Heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the Fennoscandian ice sheet. We propose that meltwater input of Heinrich event 1 significantly reduced North Atlantic Deep Water formation reducing the heat exchange between the low and high latitudes, thus delaying deglaciation by about 1500 radiocarbon years (2000 calendar years). |
format |
Article in Journal/Newspaper |
author |
Maslin, MA Shackleton, NJ Pflaumann, U |
author_facet |
Maslin, MA Shackleton, NJ Pflaumann, U |
author_sort |
Maslin, MA |
title |
Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
title_short |
Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
title_full |
Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
title_fullStr |
Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
title_full_unstemmed |
Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds |
title_sort |
surface water temperature, salinity, and density changes in the northeast atlantic during the last 45,000 years: heinrich events, deep water formation, and climatic rebounds |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
1995 |
url |
https://discovery.ucl.ac.uk/id/eprint/170786/1/94PA03040.pdf https://discovery.ucl.ac.uk/id/eprint/170786/ |
genre |
Fennoscandian Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic Northeast Atlantic Sea ice |
genre_facet |
Fennoscandian Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic Northeast Atlantic Sea ice |
op_source |
Paleoceanography , 10 (3) 527 - 544. (1995) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/170786/1/94PA03040.pdf https://discovery.ucl.ac.uk/id/eprint/170786/ |
op_rights |
open |
_version_ |
1812813454038269952 |