Chiocci, Francesco L. ... et al.-- Conferencia Internacional para conmemorar el 1er Aniversario d... more Chiocci, Francesco L. ... et al.-- Conferencia Internacional para conmemorar el 1er Aniversario de la erupcion submarina de El Hierro 2011-2012, 10-15 October 2012, El Pinar, El Hierro, Canary Islands, Spain
Submarine Mass Movements and Their Consequences: 6th International Symposium, 2014
ABSTRACT The Quaternary stratigraphic architecture of seamounts and surrounding deposits in the e... more ABSTRACT The Quaternary stratigraphic architecture of seamounts and surrounding deposits in the eastern Alboran Sea reveals at least 53 stacked MTDs in the Pollux Bank, Sabinar Bank (Sabinar Platform and Western Sabinar), Maimonides Ridge, and Adra Ridge. These MTDs are grouped into two types based on their size: smallscale MTDs (length <5 km and thickness <18 ms) and large-scale MTDs (length >5 km and thickness >18 ms). The study of these deposits has allowed us to define a close relationship between size (thickness-length) and source area gradients. The frequency of MTD events has varied between 40 and 373 kyr throughout the Quaternary (1.8 Ma to present). Correlation between individual MTDs is difficult but could be done for at least one local MTD event between Sabinar Platform and Western Sabinar (Sabinar Bank); in addition, one regional MTD event has been recognized around all of the studied seamounts. These failure events could have been triggered by tectonically controlled seismicity at both regional and local scale.
New core data from a sediment–wave field on the Demerara Outer Ridge show that the waves are main... more New core data from a sediment–wave field on the Demerara Outer Ridge show that the waves are mainly built from turbidity currents that flow northwards down the Demerara margin. The contour currents circulating parallel and obliquely to the margin are apparently not as important to wave formation as previously proposed. Detailed analysis of the sedimentary facies of cores taken on the crest and flank of a sediment wave indicates that fine-grained turbiditic deposits are dominant. Hemipelagic/pelagic deposits are interbedded with the turbidites. Sediment redistribution by contour currents was only evidenced by the presence of peculiar clay mineral assemblages and microfaunal associations, as well as some sedimentary structures such as truncations and cross-bedding. The turbiditic processes were active during the Last Glacial. In contrast, the Holocene is characterised by pelagic sedimentation. A combination of seismic and core data suggests that the sediment waves result from predominantly turbiditic depositional processes interacting with minor contour currents and synsedimentary deformation processes.
A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary reg... more A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary register in the Alboran Sea. This multiple system formed by the Atlantic and the low density and high density Mediterranean Waters, which shaped the margins and basins since the opening of the Gibraltar Strait. Three different (paleo)circulation scenarios are proposed since then: the Atlantic water Flooding;the Pliocene circulation, characterized by immature low and high density Mediterranean waters and a strong countercurrent in the Western Basin; and the Quaternary circulation, characterized by tabular Mediterranean water masses with multiple current dynamics,an increasing influence of density contrasts, and climate shifts causing major vertical and horizontal displacements of their interfaces.
The interpretation of approximately 100 km of EM12 multibeam bathymetry and backscatter data toge... more The interpretation of approximately 100 km of EM12 multibeam bathymetry and backscatter data together with high resolution TOPAS profiles obtained during a transit over the Orinoco deep-sea fan, near the Barbados accretionary prism, shows that the braided drainage pattern seen on GLORIA images by Belderson et al. (1984)corresponds to wide (∼10 km), low relief (<5 m) channels, incised by numerous
Abstract: The Oligocene to Recent Agadir turbidite system occurs in the Agadir Basin, abutting ag... more Abstract: The Oligocene to Recent Agadir turbidite system occurs in the Agadir Basin, abutting against the continental margin off South Morocco (central eastern Atlantic). This system is part of the submarine drainage system linking back to the Anti-and High Atlas mountains ...
The Ceuta Drift is an elongated-terrace feature (up to 100 km long, 28 km wide, 400 m relief, and... more The Ceuta Drift is an elongated-terrace feature (up to 100 km long, 28 km wide, 400 m relief, and 700 ms thick) located in the southwestern Alboran Sea, close to the Gibraltar Strait. It extends between 200 and 700 m water depth, parallel to the Moroccan slope. The drift stratigraphy is defined by the vertical stacking of at least five seismic units bounded by discontinuities: onlap and downlap surfaces at the bottom, and erosive surfaces at the top. Sedimentologically, the most recent deposits are defined by the vertical succesion, from bottom to top, of contouritic sandy muds, muds, and silty clays. The Ceuta Drift began to develop during the early Quaternary, when the pre-existing sea-floor morphology favoured the formation of an offshoot current system from the Mediterranean water masses. The action of this current together with sea-level changes have controlled the growth pattern of this drift.
Chiocci, Francesco L. ... et al.-- Conferencia Internacional para conmemorar el 1er Aniversario d... more Chiocci, Francesco L. ... et al.-- Conferencia Internacional para conmemorar el 1er Aniversario de la erupcion submarina de El Hierro 2011-2012, 10-15 October 2012, El Pinar, El Hierro, Canary Islands, Spain
Submarine Mass Movements and Their Consequences: 6th International Symposium, 2014
ABSTRACT The Quaternary stratigraphic architecture of seamounts and surrounding deposits in the e... more ABSTRACT The Quaternary stratigraphic architecture of seamounts and surrounding deposits in the eastern Alboran Sea reveals at least 53 stacked MTDs in the Pollux Bank, Sabinar Bank (Sabinar Platform and Western Sabinar), Maimonides Ridge, and Adra Ridge. These MTDs are grouped into two types based on their size: smallscale MTDs (length <5 km and thickness <18 ms) and large-scale MTDs (length >5 km and thickness >18 ms). The study of these deposits has allowed us to define a close relationship between size (thickness-length) and source area gradients. The frequency of MTD events has varied between 40 and 373 kyr throughout the Quaternary (1.8 Ma to present). Correlation between individual MTDs is difficult but could be done for at least one local MTD event between Sabinar Platform and Western Sabinar (Sabinar Bank); in addition, one regional MTD event has been recognized around all of the studied seamounts. These failure events could have been triggered by tectonically controlled seismicity at both regional and local scale.
New core data from a sediment–wave field on the Demerara Outer Ridge show that the waves are main... more New core data from a sediment–wave field on the Demerara Outer Ridge show that the waves are mainly built from turbidity currents that flow northwards down the Demerara margin. The contour currents circulating parallel and obliquely to the margin are apparently not as important to wave formation as previously proposed. Detailed analysis of the sedimentary facies of cores taken on the crest and flank of a sediment wave indicates that fine-grained turbiditic deposits are dominant. Hemipelagic/pelagic deposits are interbedded with the turbidites. Sediment redistribution by contour currents was only evidenced by the presence of peculiar clay mineral assemblages and microfaunal associations, as well as some sedimentary structures such as truncations and cross-bedding. The turbiditic processes were active during the Last Glacial. In contrast, the Holocene is characterised by pelagic sedimentation. A combination of seismic and core data suggests that the sediment waves result from predominantly turbiditic depositional processes interacting with minor contour currents and synsedimentary deformation processes.
A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary reg... more A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary register in the Alboran Sea. This multiple system formed by the Atlantic and the low density and high density Mediterranean Waters, which shaped the margins and basins since the opening of the Gibraltar Strait. Three different (paleo)circulation scenarios are proposed since then: the Atlantic water Flooding;the Pliocene circulation, characterized by immature low and high density Mediterranean waters and a strong countercurrent in the Western Basin; and the Quaternary circulation, characterized by tabular Mediterranean water masses with multiple current dynamics,an increasing influence of density contrasts, and climate shifts causing major vertical and horizontal displacements of their interfaces.
The interpretation of approximately 100 km of EM12 multibeam bathymetry and backscatter data toge... more The interpretation of approximately 100 km of EM12 multibeam bathymetry and backscatter data together with high resolution TOPAS profiles obtained during a transit over the Orinoco deep-sea fan, near the Barbados accretionary prism, shows that the braided drainage pattern seen on GLORIA images by Belderson et al. (1984)corresponds to wide (∼10 km), low relief (<5 m) channels, incised by numerous
Abstract: The Oligocene to Recent Agadir turbidite system occurs in the Agadir Basin, abutting ag... more Abstract: The Oligocene to Recent Agadir turbidite system occurs in the Agadir Basin, abutting against the continental margin off South Morocco (central eastern Atlantic). This system is part of the submarine drainage system linking back to the Anti-and High Atlas mountains ...
The Ceuta Drift is an elongated-terrace feature (up to 100 km long, 28 km wide, 400 m relief, and... more The Ceuta Drift is an elongated-terrace feature (up to 100 km long, 28 km wide, 400 m relief, and 700 ms thick) located in the southwestern Alboran Sea, close to the Gibraltar Strait. It extends between 200 and 700 m water depth, parallel to the Moroccan slope. The drift stratigraphy is defined by the vertical stacking of at least five seismic units bounded by discontinuities: onlap and downlap surfaces at the bottom, and erosive surfaces at the top. Sedimentologically, the most recent deposits are defined by the vertical succesion, from bottom to top, of contouritic sandy muds, muds, and silty clays. The Ceuta Drift began to develop during the early Quaternary, when the pre-existing sea-floor morphology favoured the formation of an offshoot current system from the Mediterranean water masses. The action of this current together with sea-level changes have controlled the growth pattern of this drift.
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