Shelves around the Iberian Peninsula (II)Evolutionary sedimentary patternse
- Lobo Sánchez, Francisco José
- Durán Gallego, Ruth
- Roque, Cristina
- Ribó, M.
- Carrara, G.
- Mendes, I.
- Fernández Ferrín, Carlos Alberto
- Fernández-Salas, Luis Miguel
- García Gil, Soledad
- Galparsoro, Ibon
- Rosa, F.
- Bárcenas Gascón, Patricia
ISSN: 0366-0176
Year of publication: 2015
Issue Title: Procesos geológicos en el margen continental ibérico: nuevos avances y tendencias
Volume: 126
Issue: 2-3
Pages: 377-408
Type: Article
More publications in: Boletín geológico y minero
Abstract
We present a synthetic view of continental-shelf evolutionary patterns around the Iberian Peninsula, focusing on proposed sequence stratigraphy interpretations and attempting a comparison between Atlantic- and Mediterranean-type shelf-margin constructions. Most of the studied shelves show a dominance of regressive to lowstand deposition through successive progradations, particularly evident in the Pliocene-Quaternary, documenting the influence of glacio-eustasy. Transgressive to highstand development predating the Last Glacial Maximum seems to be favoured off major rivers, but the highest variability is seen during postglacial evolution. Transgressive deposits tend to show a higher spatial variability, ranging from prograded parasequences to extensive sand sheets. Holocene highstand deposits usually show a more homogeneous character, with development of proximal wedge-shaped deposits and a distal sheet-like deposition. Atlantic continental shelves off Iberia display three different types of shelf growth: depositional shelves, shelves with restricted progradation and erosional shelves. They result from the interplay between depositional and hydrodynamic regimes, with the occurrence of a latitudinal gradation from erosional shelves in the Cantabrian continental shelf to depositional shelves in the northern Gulf of Cadiz shelf. Some shelf sectors do not correspond to this general pattern, as shelf sedimentation is mainly controlled by morpho-structural features (e.g., ria environments and shelves crossed by major tectonic accidents). The Mediterranean continental shelves of Iberia show two basic types, high- versus low-supply shelves, and their growth patterns are mainly a response to the amount of fluvial supply. The low-supply style is clearly the most frequent type, and it may show further complexity according to the occurrence of submarine canyons and/or morpho-structural control.