Sistemas de valles encajados en un margen continental sin aportes fluviales importantesPlataforma del Algarve, Golfo de Cádiz.
- A. Carrión-Torrente 1
- F.J. Lobo 1
- A. Puga-Bernabéu 2
- M. Luján 3
- I. Mendes 4
- T.J.J. Hanebuth 5
- S. Lebreiro 6
- M. García 7
- M.I. Reguera 6
- L. Antón 6
- D. Van Rooij 8
- J. Cerrillo-Escoriza 1
- 1 IACT, CSIC-Universidad de Granada
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2
Universidad de Granada
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3
Universidad de Cádiz
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4
Universidade do Algarve
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5
Coastal Carolina University
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- 6 IGME
- 7 IEO, Centro Oceanográfico de Cádiz
- 8 Renard Centre of Marine Geology, Ghent University
ISSN: 1576-5172
Any de publicació: 2021
Títol de l'exemplar: X Congreso Geológico de España
Número: 18
Pàgines: 737
Tipus: Article
Altres publicacions en: Geotemas (Madrid)
Resum
Incised valleys constitute the main course for sediment transport on continental margins from a source-to-sink perspective. This study describes two paleovalley systems off the Portuguese coast on the Gulf of Cadiz continental shelf, an offshore region that presently receives only insignificant fluvial supply. We aim to establish the controlling factors that have deter- mined the formation of these valley systems. The spatial distribution and architecture of the paleovalleys were interpreted based on a grid of high-resolution seismic profiles. Likewise, a new sediment core, obtained from the more proximal paleo- valley system, provided useful information about the dominant sedimentary processes during the most recent stage of valley sediment infilling. On the middle shelf, a paleovalley system was found showing at least four excavation phases, whose successive formation could be controlled by a sub-vertical fault system. Correlation of the excavation surfaces with the regional chronostrati- graphic framework reveals that these excavation phases occurred prior to 0.9 Ma. Along the inner shelf off the Gilão River mouth, a second paleovalley system was identified, which was similarly characterized by several phases of successive exca- vation. The most recent phase is associated with the regionwide erosive unconformity formed during the Last Glacial Maxi- mum shelf exposure, suggesting that the evolution of this system was driven mainly by glacio-eustasy.