Change in the North Atlantic circulation associated with the mid-Pleistocene transition
The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer ass...
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ftcopernicus:oai:publications.copernicus.org:cp67331 2023-05-15T15:13:11+02:00 Change in the North Atlantic circulation associated with the mid-Pleistocene transition Martin-Garcia, Gloria M. Sierro, Francisco J. Flores, José A. Abrantes, Fátima 2018-11-29 application/pdf https://doi.org/10.5194/cp-14-1639-2018 https://cp.copernicus.org/articles/14/1639/2018/ eng eng doi:10.5194/cp-14-1639-2018 https://cp.copernicus.org/articles/14/1639/2018/ eISSN: 1814-9332 Text 2018 ftcopernicus https://doi.org/10.5194/cp-14-1639-2018 2020-07-20T16:23:04Z The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37 ∘ 34.285 ′ N, 10 ∘ 7.562 ′ W; 2585 m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55 ∘ N, basin-wide paleoceanographic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south–north, and east–west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles. Text Arctic Ice Sheet NADW north atlantic current North Atlantic Deep Water North Atlantic Copernicus Publications: E-Journals Arctic Climate of the Past 14 11 1639 1651 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37 ∘ 34.285 ′ N, 10 ∘ 7.562 ′ W; 2585 m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55 ∘ N, basin-wide paleoceanographic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south–north, and east–west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles. |
format |
Text |
author |
Martin-Garcia, Gloria M. Sierro, Francisco J. Flores, José A. Abrantes, Fátima |
spellingShingle |
Martin-Garcia, Gloria M. Sierro, Francisco J. Flores, José A. Abrantes, Fátima Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
author_facet |
Martin-Garcia, Gloria M. Sierro, Francisco J. Flores, José A. Abrantes, Fátima |
author_sort |
Martin-Garcia, Gloria M. |
title |
Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
title_short |
Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
title_full |
Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
title_fullStr |
Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
title_full_unstemmed |
Change in the North Atlantic circulation associated with the mid-Pleistocene transition |
title_sort |
change in the north atlantic circulation associated with the mid-pleistocene transition |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-14-1639-2018 https://cp.copernicus.org/articles/14/1639/2018/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Ice Sheet NADW north atlantic current North Atlantic Deep Water North Atlantic |
genre_facet |
Arctic Ice Sheet NADW north atlantic current North Atlantic Deep Water North Atlantic |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-14-1639-2018 https://cp.copernicus.org/articles/14/1639/2018/ |
op_doi |
https://doi.org/10.5194/cp-14-1639-2018 |
container_title |
Climate of the Past |
container_volume |
14 |
container_issue |
11 |
container_start_page |
1639 |
op_container_end_page |
1651 |
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1766343778050768896 |