Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/225560
COMPARTIR / EXPORTAR:
logo share SHARE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE

Invitar a revisión por pares abierta
Título

How deep does sand deposits in the Alentejo basin (Gulf of Cadiz) reach? Evaluating slope stability from bottom-current activities through time

AutorMencaroni, Davide CSIC ORCID ; Urgeles, Roger CSIC ORCID ; Ford, Jonathan; Llopart, Jaume CSIC ORCID ; Sànchez-Serra, Cristina CSIC ORCID ; Calahorrano, Alcinoe CSIC ORCID ; Brito, Pedro; Lo Iacono, Claudio CSIC ORCID; Bartolomé, Rafael CSIC ORCID CVN ; Gràcia, Eulàlia CSIC ORCID ; Rebesco, Michele; Camerlenghi, Angelo; Bellwald, Benjamin
Fecha de publicación4-may-2020
EditorEuropean Geosciences Union
CitaciónEGU General Assembly (2020)
ResumenContourite deposits are generated by the interplay between deepwater bottom-currents, sediment supply and seafloor topography. The Gulf of Cadiz, in the Southwest Iberian margin, is a famous example of extensive contourite deposition driven by the Mediterranean Outflow Water (MOW), which exits the Strait of Gibraltar, flows northward following the coastline and distributes the sediments coming from the Guadalquivir and Guadiana rivers. The MOW and related contourite deposits affect the stability of the SW Iberian margin in several ways: on one hand it increases the sedimentation rate, favoring the development of excess pore pressure, while on the other hand, by depositing sand it allows pore water pressure to dissipate, potentially increasing the stability of the slope. In the Gulf of Cadiz, grain size distribution of contourite deposits is influenced by the seafloor morphology, which splits the MOW in different branches, and by the alternation of glacial and interglacial periods that affected the MOW hydrodynamic regimes. Fine clay packages alternates with clean sand formations according to the capacity of transport of the bottom-current in a specific area. Generally speaking, coarser deposits are found in the areas of higher MOW flow energy, such as in the shallower part of the slope or in the area closer to the Strait of Gibraltar, while at higher water depths the sedimentation shifts to progressively finer grain sizes as the MOW gets weaker. Previous works show that at present-day the MOW flows at a maximum depth of 1400 m, while during glacial periods the bottom-current could have reached higher depths. In this study we derived the different maximum depths at which the MOW flowed by analyzing the distribution of sands at different depths along the Alentejo basin slope, in the Northern sector of the Gulf of Cadiz. Here we show how changes in sand distribution along slope, within the stratigraphic units deposited between the Neogene and the present day, are driven by glacial – interglacial period alternation that influenced the hydrodynamic regime of the MOW. By deriving the depositional history of sand in the Alentejo basin, we are able to correlate directly the influence that climatic cycles had on the MOW activity. Furthermore, by interpreting new multi-channel seismic profiles we have been able to derive a detailed facies characterization of the uppermost part of the Gulf of Cadiz. An accurate definition of sand distribution along slope plays an important role in evaluating the stability of the slope itself, e.g. to understand if the sediments may be subjected to excess pore pressure generation. As sand distribution is a direct function of the bottom-current transport capacity, the ultimate goal of this study is to understand how climate variations can affect the stability of submarine slope by depositing contourite-related sand
DescripciónEuropean Geosciences Union (EGU) General Assembly 2020, 4-8 May 2020
Versión del editorhttps://doi.org/10.5194/egusphere-egu2020-18904
URIhttp://hdl.handle.net/10261/225560
DOI10.5194/egusphere-egu2020-18904
Aparece en las colecciones: (ICM) Comunicaciones congresos




Ficheros en este ítem:
Fichero Descripción Tamaño Formato
Mencaroni_et_al_2020_presentation.pdf4,65 MBAdobe PDFVista previa
Visualizar/Abrir
Mostrar el registro completo

CORE Recommender

Page view(s)

126
checked on 19-mar-2024

Download(s)

183
checked on 19-mar-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.