Acoustic evidences of along-slope processes associated with mass movement deposits on the Madeira Island lower slope (Eastern Central Atlantic).
Authors
Roque, C. (Cristina); Madureira, P. (Pedro); Hernández-Molina, F.J. (Francisco Javier); Santos de Campos, A.; Quartau, R.; Carrara, G.; Brandão, F.; Vázquez, J.T. (Juan Tomás); Somoza-Losada, L. (Luis)Editor/s
Díaz-del-Río-Español, V. (Víctor); Bárcenas-Gascón, P. (Patricia); Fernández-Salas, L.M. (Luis Miguel); López-González, N. (Nieves); Palomino, D. (Desirée); Rueda, J.L. (José Luis); Vázquez, J.T. (Juan Tomás)Date
2015-09-21Type
book partKeywords
alongslope processesmass movements
Madeira lower slope
Madeira drift
Central Atlantic
Abstract
The Madeira Island lower slope has been build-up mostly by along slope-processes
associated with mass movement deposits as seen in GEBCO bathymetry, multibeam bathymetry,
Parasound echosounder profiles and multichannel seismic reflection profiles. A plastered contourite
drift (Madeira Drift) developed on this lower slope, being composed of seismic units D1, D2 and D3.
The most probable water mass responsible for its deposition is the Antarctica Bottom Water
(AABW). The youngest sediments of seismic units D2 and D3 are affected by gravity-driven
processes, probably slumps and debris flows, which moved downslope towards west. Parasound
profiles show evidences of such mass movements on present-day seabottom (e.g. diffraction
hyperbolae echoes) but also of past-events buried within the contourite sediments. These older
debris flows are recognized by semitransparent/transparent acoustic facies and lenticular shape.
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