Caracterización de los sedimentos superficiales en tres sistemas deposicionales contorníticos (Golfo de Cádiz, Cabo Ortegal y El Cachucho)implicaciones conceptuales
- I. Alejo 1
- M.A. Nombela 1
- G. Ercilla 2
- R.E. Brackenridge 3
- G. Francés 1
- M. Pérez-Arlucea 1
- A. Mena 1
- F.J. Hernández-Molina 1
- D.A.V. Stow 3
- T. Medialdea 4
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1
Universidade de Vigo
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- 2 CSIC, Instituto Ciencias del Mar
- 3 ECOSSE, Heriot-Watt University, Edinburgh
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4
Instituto Geológico y Minero de España
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ISSN: 1576-5172
Ano de publicación: 2012
Título do exemplar: VIII Congreso Geológico de España, Oviedo, 17-19 de julio, 2012.
Número: 13
Páxinas: 1781-1784
Tipo: Artigo
Outras publicacións en: Geotemas (Madrid)
Resumo
Compositional, mineralogical and grain size data from 13 superficial samples recovered between 490 and 1144 m water depth in three Contourite Depositional Systems (CDSs): the Gulf of Cadiz, Ortegal Spur and El Cachucho are presented. First surficial centimeter was analysed in different contourite features: depositional (drifts), erosive (moats) and mixed (terraces). Analysed sediments show a broad variability in grain size, from bioclastic gravels to azoic fine silts. There is no clear particle size difference between the three studied CDSs, but there is a similar textural trend between the contourite features and the textural pattern. Coarser samples are located both in moats and terraces, with medium (300 µm in the El Cachucho) and coarse sands (600 µm in Gulf of Cadiz and Ortegal Spur). Many samples have foraminifers and glauconite in different percentages. The most abundant minerals in all samples are quartz (34.7-77.8%) and calcite (14.1-42.9%). Magnesium calcite (1-15.8%) appears in all samples,, and albite (1-5%) and microcline (2- 5%) occur in most of them Surface sediment characterization and classification is essential for contourite facies estimation, not well established yet.