Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton

Variations in the assemblage and abundance of coccoliths reveal changes in oceanic and atmospheric dynamics in the Guyana Basin over the last climatic cycle, mainly linked to latitudinal variations in the ITCZ (Intertropical Convergence Zone). Records of the N ratio (a palaeoproductivity index of co...

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Autores: López-Otálvaro, G.E., Flores Villarejo, José Abel, Sierro Sánchez, Francisco Javier, Cacho Lascorz, Isabel, Grimalt Obrador, Joan, Michel, E., Cortijo, E., Labeyrie, L.
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2009
País:España
Recursos:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/120509
Acesso em linha:https://hdl.handle.net/2445/120509
Access Level:acceso abierto
Palavra-chave:Paleoclimatologia
Guyana
Paleoceanografia
Plistocè
Paleoclimatology
Paleoceanography
Pleistocene
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spelling Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplanktonLópez-Otálvaro, G.E.Flores Villarejo, José AbelSierro Sánchez, Francisco JavierCacho Lascorz, IsabelGrimalt Obrador, JoanMichel, E.Cortijo, E.Labeyrie, L.PaleoclimatologiaGuyanaPaleoceanografiaPlistocèPaleoclimatologyGuyanaPaleoceanographyPleistoceneVariations in the assemblage and abundance of coccoliths reveal changes in oceanic and atmospheric dynamics in the Guyana Basin over the last climatic cycle, mainly linked to latitudinal variations in the ITCZ (Intertropical Convergence Zone). Records of the N ratio (a palaeoproductivity index of coccolithophores) allowed us to monitor nutri-thermocline fluctuations. Nannofossil accumulation rates (NAR) vary closely with the N ratio, indicating a strong correlation between these two palaeoproductivity proxies. Decreases in the N ratio and NAR values suggest lower palaeoproductivity during glacial substages, indicating a deep nutri-thermocline (deep stratification of the mixed layer) as a consequence of the piling up of warm water dragged by the NEC. This setting was favoured by the southern shift of the ITCZ and Trade winds which blew perpendicular to the Guyana coast. By contrast, increases in the N ratio and NAR values revealed higher palaeoproductivity during interglacial substages, suggesting a shoaling of the nutri-thermocline. This scenario is favoured by a northward displacement of the ITCZ with the southeast Trade winds blowing alongshore. Additionally, palaeoproductivity changes during substages of Marine Isotope Stage (MIS) 6-5 are of much higher amplitude than those recorded in substages of MIS 4-2 and the early Holocene. Similarities between the palaeoproductivity and the 65° N summer insolation records, suggest a link between the depth of nutri-thermocline, the latitudinal migration of the ITCZ and ice-sheet changes in the Northern Hemisphere.Copernicus Publications2009info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/120509Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció del document publicat a: https://doi.org/10.5194/ee-4-1-2009eEarth, 2009, vol. 4, p. 1-13https://doi.org/10.5194/ee-4-1-2009cc-by (c) López-Otálvaro, G.E. et al., 2009http://creativecommons.org/licenses/by/3.0/esinfo:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1205092026-05-27T06:46:51Z
dc.title.none.fl_str_mv Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
title Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
spellingShingle Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
López-Otálvaro, G.E.
Paleoclimatologia
Guyana
Paleoceanografia
Plistocè
Paleoclimatology
Guyana
Paleoceanography
Pleistocene
title_short Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
title_full Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
title_fullStr Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
title_full_unstemmed Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
title_sort Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton
dc.creator.none.fl_str_mv López-Otálvaro, G.E.
Flores Villarejo, José Abel
Sierro Sánchez, Francisco Javier
Cacho Lascorz, Isabel
Grimalt Obrador, Joan
Michel, E.
Cortijo, E.
Labeyrie, L.
author López-Otálvaro, G.E.
author_facet López-Otálvaro, G.E.
Flores Villarejo, José Abel
Sierro Sánchez, Francisco Javier
Cacho Lascorz, Isabel
Grimalt Obrador, Joan
Michel, E.
Cortijo, E.
Labeyrie, L.
author_role author
author2 Flores Villarejo, José Abel
Sierro Sánchez, Francisco Javier
Cacho Lascorz, Isabel
Grimalt Obrador, Joan
Michel, E.
Cortijo, E.
Labeyrie, L.
author2_role author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Paleoclimatologia
Guyana
Paleoceanografia
Plistocè
Paleoclimatology
Guyana
Paleoceanography
Pleistocene
topic Paleoclimatologia
Guyana
Paleoceanografia
Plistocè
Paleoclimatology
Guyana
Paleoceanography
Pleistocene
description Variations in the assemblage and abundance of coccoliths reveal changes in oceanic and atmospheric dynamics in the Guyana Basin over the last climatic cycle, mainly linked to latitudinal variations in the ITCZ (Intertropical Convergence Zone). Records of the N ratio (a palaeoproductivity index of coccolithophores) allowed us to monitor nutri-thermocline fluctuations. Nannofossil accumulation rates (NAR) vary closely with the N ratio, indicating a strong correlation between these two palaeoproductivity proxies. Decreases in the N ratio and NAR values suggest lower palaeoproductivity during glacial substages, indicating a deep nutri-thermocline (deep stratification of the mixed layer) as a consequence of the piling up of warm water dragged by the NEC. This setting was favoured by the southern shift of the ITCZ and Trade winds which blew perpendicular to the Guyana coast. By contrast, increases in the N ratio and NAR values revealed higher palaeoproductivity during interglacial substages, suggesting a shoaling of the nutri-thermocline. This scenario is favoured by a northward displacement of the ITCZ with the southeast Trade winds blowing alongshore. Additionally, palaeoproductivity changes during substages of Marine Isotope Stage (MIS) 6-5 are of much higher amplitude than those recorded in substages of MIS 4-2 and the early Holocene. Similarities between the palaeoproductivity and the 65° N summer insolation records, suggest a link between the depth of nutri-thermocline, the latitudinal migration of the ITCZ and ice-sheet changes in the Northern Hemisphere.
publishDate 2009
dc.date.none.fl_str_mv 2009
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/120509
url https://hdl.handle.net/2445/120509
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.5194/ee-4-1-2009
eEarth, 2009, vol. 4, p. 1-13
https://doi.org/10.5194/ee-4-1-2009
dc.rights.none.fl_str_mv cc-by (c) López-Otálvaro, G.E. et al., 2009
http://creativecommons.org/licenses/by/3.0/es
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc-by (c) López-Otálvaro, G.E. et al., 2009
http://creativecommons.org/licenses/by/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Copernicus Publications
publisher.none.fl_str_mv Copernicus Publications
dc.source.none.fl_str_mv Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,301629

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