Por favor, use este identificador para citar o enlazar a este item:
http://hdl.handle.net/10261/277063
COMPARTIR / EXPORTAR:
SHARE CORE BASE | |
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE | |
Título: | Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz |
Autor: | Martín Lebreiro, Susana CSIC ORCID; Antón López, Laura Ángela; Reguera García, M. Isabel; Marzocchi, Alice | Palabras clave: | Quaternary paleoceanography climate modelling North Atlantic foraminifers stable isotopes sortable silt Mediterranean outflow Morocco contourite drift Gulf of Cadiz Golfo de Cádiz |
Fecha de publicación: | 2018 | Editor: | Elsevier | Citación: | Quaternary Science Reviews (2018), 197, p.92-111 | Resumen: | 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). | Versión del editor: | https://www.sciencedirect.com/science/article/pii/S027737911730999X | URI: | http://hdl.handle.net/10261/277063 | DOI: | https://doi.org/10.1016/j.quascirev.2018.07.036 | ISSN: | 0277-3791 |
Aparece en las colecciones: | (IGME) Artículos |
Ficheros en este ítem:
Fichero | Descripción | Tamaño | Formato | |
---|---|---|---|---|
paleoceanographic_climatic_implications_2018.pdf | Artículo | 4,28 MB | Adobe PDF | Visualizar/Abrir |
palaeoceanographic_climatic_implications_2018_preprint-aceptado.pdf | Preprint aceptado | 9,57 MB | Adobe PDF | Visualizar/Abrir |
paleoceanographic_climatic_implications_material_suplementario_2018.pdf | Material complementario | 1,14 MB | Adobe PDF | Visualizar/Abrir |
CORE Recommender
Page view(s)
23
checked on 28-abr-2024
Download(s)
43
checked on 28-abr-2024
Google ScholarTM
Check
Altmetric
Altmetric
NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.