Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz

The presence of contourite drifts in the southern Gulf of Cadiz (GoC) along the Moroccan margin raises questions about the (re)circulation of Mediterranean Outflow Water (MOW) in the GoC and the origin of the currents depositing them. Here, we compare two cores representative of Iberian and Moroccan...

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Autores: Lebreiro, Susana M., Antón López, Laura Ángela, Reguera García, M. Isabel, Marzocchi, Alice
Tipo de recurso: artículo
Fecha de publicación:2018
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/277063
Acceso en línea:http://hdl.handle.net/10261/277063
https://doi.org/10.1016/j.quascirev.2018.07.036
Access Level:acceso abierto
Palabra clave:Quaternary
paleoceanography
climate modelling
North Atlantic
foraminifers
stable isotopes
sortable silt
Mediterranean outflow
Morocco contourite drift
Gulf of Cadiz
Golfo de Cádiz
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spelling Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of CadizLebreiro, Susana M.Antón López, Laura ÁngelaReguera García, M. IsabelMarzocchi, AliceQuaternarypaleoceanographyclimate modellingNorth Atlanticforaminifersstable isotopessortable siltMediterranean outflowMorocco contourite driftGulf of CadizGolfo de CádizThe presence of contourite drifts in the southern Gulf of Cadiz (GoC) along the Moroccan margin raises questions about the (re)circulation of Mediterranean Outflow Water (MOW) in the GoC and the origin of the currents depositing them. Here, we compare two cores representative of Iberian and Moroccan contourite drifts, covering the last 22 kyr. Although the whole sequence is contouritic in character, it reflects the interaction of distinctive silty-contourite facies (high flow velocity periods) imbedded in muddy-contourite facies (low flow velocity periods). Evidence from benthic foraminifera d13C, sortable silt grain-size, oceanographic CTD profiles and numerical simulations, indicate the Mediterranean water mass as the source of the southern contourite deposits. Our data, therefore, suggests an additional branch of upper-MOW veering southwards off the Straits of Gibraltar along the Moroccan margin. During MIS-(Marine Isotope Stage) 2, upper-MOW was a sluggish current while in the Holocene upper-MOW dominated as a fast, semi-steady flow. Throughout the deglaciation, silty contourites associated with higher flow speeds were deposited in the northern and southern GoC during cold events such as Heinrich Stadial 1 (HS1) and the Younger Dryas, forced by global millennial-scale climate variability. Millennial variability also appears to drive the deposition of silty-contourites in the Holocene. We estimated an average duration of 1 ka for the process of depositing a fast contourite unit. The case of silty-contourite I6 (within HS1) allows us to illustrate with extremely high resolution a “rapid” sequential change in circulation, with gradual slow-down of dense Mediterranean water while surface was freshening (HS1), provoking injection of high-salinity intermediate waters (via contour-currents) into the GoC,and hence the North Atlantic. The subsequent brief collapse of dense water formation in the Mediterranean Sea triggered a major increase in sea surface temperatures (10 C/ka) in the GoC, developing into the next interstadial (Bølling/Allerød). The impact of Mediterranean intermediate waters is manifested here by triggering a substantial rearrangement of intermediate and deep circulation in the North Atlantic, which would have further impacted the Atlantic Meridional Overturning Circulation (AMOC).Instituto Geológico y Minero de España, EspañaUnidad de Tres Cantos, Instituto Geológico y Minero de España, EspañaNational Oceanography Centre, Reino UnidoElsevierMinisterio de Ciencia e Innovación (España)European Science Foundation202220222018info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/277063https://doi.org/10.1016/j.quascirev.2018.07.036reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#CTM2008-06399-CO4-02/MAREuromargins project 01-LEC-EMA24F/CYCIT REN2002-11669-E/MARhttps://www.sciencedirect.com/science/article/pii/S027737911730999Xinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2770632026-05-22T06:33:51Z
dc.title.none.fl_str_mv Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
title Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
spellingShingle Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
Lebreiro, Susana M.
Quaternary
paleoceanography
climate modelling
North Atlantic
foraminifers
stable isotopes
sortable silt
Mediterranean outflow
Morocco contourite drift
Gulf of Cadiz
Golfo de Cádiz
title_short Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
title_full Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
title_fullStr Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
title_full_unstemmed Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
title_sort Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
dc.creator.none.fl_str_mv Lebreiro, Susana M.
Antón López, Laura Ángela
Reguera García, M. Isabel
Marzocchi, Alice
author Lebreiro, Susana M.
author_facet Lebreiro, Susana M.
Antón López, Laura Ángela
Reguera García, M. Isabel
Marzocchi, Alice
author_role author
author2 Antón López, Laura Ángela
Reguera García, M. Isabel
Marzocchi, Alice
author2_role author
author
author
dc.contributor.none.fl_str_mv Ministerio de Ciencia e Innovación (España)
European Science Foundation
dc.subject.none.fl_str_mv Quaternary
paleoceanography
climate modelling
North Atlantic
foraminifers
stable isotopes
sortable silt
Mediterranean outflow
Morocco contourite drift
Gulf of Cadiz
Golfo de Cádiz
topic Quaternary
paleoceanography
climate modelling
North Atlantic
foraminifers
stable isotopes
sortable silt
Mediterranean outflow
Morocco contourite drift
Gulf of Cadiz
Golfo de Cádiz
description The presence of contourite drifts in the southern Gulf of Cadiz (GoC) along the Moroccan margin raises questions about the (re)circulation of Mediterranean Outflow Water (MOW) in the GoC and the origin of the currents depositing them. Here, we compare two cores representative of Iberian and Moroccan contourite drifts, covering the last 22 kyr. Although the whole sequence is contouritic in character, it reflects the interaction of distinctive silty-contourite facies (high flow velocity periods) imbedded in muddy-contourite facies (low flow velocity periods). Evidence from benthic foraminifera d13C, sortable silt grain-size, oceanographic CTD profiles and numerical simulations, indicate the Mediterranean water mass as the source of the southern contourite deposits. Our data, therefore, suggests an additional branch of upper-MOW veering southwards off the Straits of Gibraltar along the Moroccan margin. During MIS-(Marine Isotope Stage) 2, upper-MOW was a sluggish current while in the Holocene upper-MOW dominated as a fast, semi-steady flow. Throughout the deglaciation, silty contourites associated with higher flow speeds were deposited in the northern and southern GoC during cold events such as Heinrich Stadial 1 (HS1) and the Younger Dryas, forced by global millennial-scale climate variability. Millennial variability also appears to drive the deposition of silty-contourites in the Holocene. We estimated an average duration of 1 ka for the process of depositing a fast contourite unit. The case of silty-contourite I6 (within HS1) allows us to illustrate with extremely high resolution a “rapid” sequential change in circulation, with gradual slow-down of dense Mediterranean water while surface was freshening (HS1), provoking injection of high-salinity intermediate waters (via contour-currents) into the GoC,and hence the North Atlantic. The subsequent brief collapse of dense water formation in the Mediterranean Sea triggered a major increase in sea surface temperatures (10 C/ka) in the GoC, developing into the next interstadial (Bølling/Allerød). The impact of Mediterranean intermediate waters is manifested here by triggering a substantial rearrangement of intermediate and deep circulation in the North Atlantic, which would have further impacted the Atlantic Meridional Overturning Circulation (AMOC).
publishDate 2018
dc.date.none.fl_str_mv 2018
2022
2022
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/277063
https://doi.org/10.1016/j.quascirev.2018.07.036
url http://hdl.handle.net/10261/277063
https://doi.org/10.1016/j.quascirev.2018.07.036
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
CTM2008-06399-CO4-02/MAR
Euromargins project 01-LEC-EMA24F/CYCIT REN2002-11669-E/MAR
https://www.sciencedirect.com/science/article/pii/S027737911730999X
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,81155

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