International Geologiical Congress - Oslo 2008


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Talismán Slide, western slope of Hatton Bank (NE Atlantic Acean): Morphological features


Miriam Sayago-Gil, Instituto Español de Oceanografía (Spain)
David Long, British Geological Survey (United Kingdom)
Victor Diaz-del-Rio, Instituto Español de Oceanografía (Spain)
Luis Miguel Fernández-Salas, Instituto Español de Oceanografía (Spain)
Kennet Hitchen, British Geological Survey (United Kingdom)
Desirée Palomino-Cantero, Instituto Español de Oceanografía (Spain)
Pablo Durán-Muñoz, Instituto Español de Oceanografía (Spain)


The Spanish interdisciplinary research project ECOVUL/ARPA is focused on the western slope of Hatton Bank (Hatton-Rockall Plateau, NE Atlantic Ocean). This scientific contribution is based on data collected by "Instituto Español de Oceanografía": multibeam bathymetry (SIMRAD-KONGSBERG-EM300) and very-high resolution seismic profiles (TOPAS). The study area is located at 57°41.45N; 20°04.98W and 57°25.27N; 20°28.11W on the Hatton Drift. Data reveals a special morphology identified as a landslide named "Talismán Slide", covering an area of 194km2, extending 15km downslope. It is the first slide reported from the Hatton Bank. Note that the area surveyed covers only a part of the slide. It is orientated SE-NW with its headwall at 1358m water depth, and extends to at least 1900m depth. The 7.7km headwall scarp shows a NE-SW trend with an irregular zigzag form. The scarp varies in height between 50 and 76m and has a slope angle of 30°.
The northern sidewall has a linear trend (SE-NW) with a scarp height of up to 100m and slope angle of 34°. The southern sidewall has a more irregular form, comparable to the headwall, with a scarp height of 50m decreasing downslope to 30m and it has a slope angle of 25° to 30°. The slide mass is displayed as sinuous and discontinuous morphologies, many step-forming detached, some of them as positive relieves and some others like negatives, mainly perpendicular to the scar, along on the direction of slide motion. Three facies types can be observed in seismic sections: transparent, stratified and chaotic. The slip plane presents a very high-amplitude reflector. Data collected is interpreted to have failed along a surface at least partly made up of contourite sands. The trigger mechanism could be a combination of several causative factors, as can be the susceptibility to liquefaction of sandier sediments under dynamical loading or the presence of gas in the surrounding area.


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