The last termination in the central South Atlantic
Lake sediments and peat deposits from two basins on Nightingale Island (37 degrees S), in the Tristan da Cunha archipelago, South Atlantic, have been analyzed. The studies were focused on the time period 16.2-10.0 cal ka BP, determined by 36 C-14 dates from the two sequences. A wide variety of proxi...
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Online Access: | https://lup.lub.lu.se/record/7972214 https://doi.org/10.1016/j.quascirev.2015.07.003 |
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ftulundlup:oai:lup.lub.lu.se:b8c11fd1-4b93-44a2-912b-83648ccd1b61 2023-05-15T13:35:34+02:00 The last termination in the central South Atlantic Ljung, Karl Holmgren, Sofia Kylander, Malin Sjolte, Jesper Van der Putten, Nathalie Kageyama, Masa Porter, Charles T. Björck, Svante 2015 https://lup.lub.lu.se/record/7972214 https://doi.org/10.1016/j.quascirev.2015.07.003 eng eng Elsevier https://lup.lub.lu.se/record/7972214 http://dx.doi.org/10.1016/j.quascirev.2015.07.003 wos:000359889700013 scopus:84938054754 Quaternary Science Reviews; 123, pp 193-214 (2015) ISSN: 0277-3791 Geology Bipolar see-saw climate pattern front Subtropical Southern hemisphere zonal circulation Tristan da Cunha South Atlantic Last termination Model simulation Multiproxy study contributiontojournal/article info:eu-repo/semantics/article text 2015 ftulundlup https://doi.org/10.1016/j.quascirev.2015.07.003 2023-02-01T23:29:18Z Lake sediments and peat deposits from two basins on Nightingale Island (37 degrees S), in the Tristan da Cunha archipelago, South Atlantic, have been analyzed. The studies were focused on the time period 16.2-10.0 cal ka BP, determined by 36 C-14 dates from the two sequences. A wide variety of proxies were used, including pollen and diatom analyzes, biogenic silica content, C and N analyzes, stable isotopes (C-13 and N-15), elemental concentrations and magnetic susceptibility measurements, to detect environmental changes that can be related to shifts of the circulation belts of the Southern Ocean. In addition, climate model simulations were carried out. We find that the sediments are underlain by a >2 cal ka BP long hiatus, possibly representing a dried-out lake bed. The climate simulations corroborate that the area might have been exposed to arid conditions as a consequence of the Heinrich I event in the north and a southward displacement of the ITCZ. The development on the island after 16.2 cal ka BP is determined by the position of the Subtropical Front (STF) and the Southern Hemisphere Westerlies (SHW). The period 16.2-14.75 cal ka BP was characterized by varying influence from SHW and with STF situated south of Tristan da Cunha, ending with a humidity peak and cooler conditions. The stable conditions 14.7-14.1 cal ka BP with cool and fairly arid conditions imply that STF and SHW were both north of the islands during the first part of the Antarctic Cold Reversal. The most unstable period, 14.1-12.7 cal ka BP, indicates incessant latitudinal shifts of the zonal circulation, perhaps related to climate variability in the Northern Hemisphere and bipolar seesaw mechanisms as the strength of the Atlantic Meridional Overturning Circulation (AMOC) varied. At 12.7 cal ka BP the Holocene warming began with a gradually drier and warmer climate as a result of a dampened AMOC during the Younger Dryas cooling in the north with ITCZ, STF and SHW being displaced southwards. Peak warming seems to have occurred in the ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Lund University Publications (LUP) Antarctic In ENVELOPE(-132.619,-132.619,67.550,67.550) Southern Ocean The Antarctic Tristan ENVELOPE(140.900,140.900,-66.735,-66.735) Quaternary Science Reviews 123 193 214 |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Geology Bipolar see-saw climate pattern front Subtropical Southern hemisphere zonal circulation Tristan da Cunha South Atlantic Last termination Model simulation Multiproxy study |
spellingShingle |
Geology Bipolar see-saw climate pattern front Subtropical Southern hemisphere zonal circulation Tristan da Cunha South Atlantic Last termination Model simulation Multiproxy study Ljung, Karl Holmgren, Sofia Kylander, Malin Sjolte, Jesper Van der Putten, Nathalie Kageyama, Masa Porter, Charles T. Björck, Svante The last termination in the central South Atlantic |
topic_facet |
Geology Bipolar see-saw climate pattern front Subtropical Southern hemisphere zonal circulation Tristan da Cunha South Atlantic Last termination Model simulation Multiproxy study |
description |
Lake sediments and peat deposits from two basins on Nightingale Island (37 degrees S), in the Tristan da Cunha archipelago, South Atlantic, have been analyzed. The studies were focused on the time period 16.2-10.0 cal ka BP, determined by 36 C-14 dates from the two sequences. A wide variety of proxies were used, including pollen and diatom analyzes, biogenic silica content, C and N analyzes, stable isotopes (C-13 and N-15), elemental concentrations and magnetic susceptibility measurements, to detect environmental changes that can be related to shifts of the circulation belts of the Southern Ocean. In addition, climate model simulations were carried out. We find that the sediments are underlain by a >2 cal ka BP long hiatus, possibly representing a dried-out lake bed. The climate simulations corroborate that the area might have been exposed to arid conditions as a consequence of the Heinrich I event in the north and a southward displacement of the ITCZ. The development on the island after 16.2 cal ka BP is determined by the position of the Subtropical Front (STF) and the Southern Hemisphere Westerlies (SHW). The period 16.2-14.75 cal ka BP was characterized by varying influence from SHW and with STF situated south of Tristan da Cunha, ending with a humidity peak and cooler conditions. The stable conditions 14.7-14.1 cal ka BP with cool and fairly arid conditions imply that STF and SHW were both north of the islands during the first part of the Antarctic Cold Reversal. The most unstable period, 14.1-12.7 cal ka BP, indicates incessant latitudinal shifts of the zonal circulation, perhaps related to climate variability in the Northern Hemisphere and bipolar seesaw mechanisms as the strength of the Atlantic Meridional Overturning Circulation (AMOC) varied. At 12.7 cal ka BP the Holocene warming began with a gradually drier and warmer climate as a result of a dampened AMOC during the Younger Dryas cooling in the north with ITCZ, STF and SHW being displaced southwards. Peak warming seems to have occurred in the ... |
format |
Article in Journal/Newspaper |
author |
Ljung, Karl Holmgren, Sofia Kylander, Malin Sjolte, Jesper Van der Putten, Nathalie Kageyama, Masa Porter, Charles T. Björck, Svante |
author_facet |
Ljung, Karl Holmgren, Sofia Kylander, Malin Sjolte, Jesper Van der Putten, Nathalie Kageyama, Masa Porter, Charles T. Björck, Svante |
author_sort |
Ljung, Karl |
title |
The last termination in the central South Atlantic |
title_short |
The last termination in the central South Atlantic |
title_full |
The last termination in the central South Atlantic |
title_fullStr |
The last termination in the central South Atlantic |
title_full_unstemmed |
The last termination in the central South Atlantic |
title_sort |
last termination in the central south atlantic |
publisher |
Elsevier |
publishDate |
2015 |
url |
https://lup.lub.lu.se/record/7972214 https://doi.org/10.1016/j.quascirev.2015.07.003 |
long_lat |
ENVELOPE(-132.619,-132.619,67.550,67.550) ENVELOPE(140.900,140.900,-66.735,-66.735) |
geographic |
Antarctic In Southern Ocean The Antarctic Tristan |
geographic_facet |
Antarctic In Southern Ocean The Antarctic Tristan |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Quaternary Science Reviews; 123, pp 193-214 (2015) ISSN: 0277-3791 |
op_relation |
https://lup.lub.lu.se/record/7972214 http://dx.doi.org/10.1016/j.quascirev.2015.07.003 wos:000359889700013 scopus:84938054754 |
op_doi |
https://doi.org/10.1016/j.quascirev.2015.07.003 |
container_title |
Quaternary Science Reviews |
container_volume |
123 |
container_start_page |
193 |
op_container_end_page |
214 |
_version_ |
1766067257378603008 |