Storfjorden Trough Mouth Fan (Western Barents Sea): slope failures in polar continental margins; significance of stress changes and fluid migration induced by glacial cycles

Memoria de tesis doctoral presentada por Jaume Llopart Serra para optar al grado de Doctor por la Universitat de Barcelona (UB), realizada bajo la dirección del Dr. Roger Urgeles Esclasans del Institut de Ciències del Mar (ICM-CSIC) y del Dr. Angelo Camerlenghi.-- 231 pagesLate Quaternary climate variations controlled glacial advances and retreats to the shelf edge and therefore the evolution of high latitude continental margins. The variations in ice extension modulated sediment supply to the continental slope resulting in a particular shape and stratigraphy but also exerted a major control on stresses imposed on marine sediments and likely had a major control on fluid flow pattern. This thesis investigates the sedimentary, stratigraphic and hydrogeologic evolution of two Arctic Trough Mouth Fans (TMFs), the Storfjorden and Kveithola TMFs in the NW Barents Sea, from ~2.7 Ma to Present, and identifies how such evolution affected slope instability of the TMFs. The research is carried out by means of sub-bottom and seismic reflection profiles, multibeam bathymetry data and sediment cores on which sedimentological and geotechnical analysis have been performed. Numerical finite elements models allow inferring the detailed stratigraphic architecture and hydrogeological evolution of the TMFs. We found that the Storfjorden and Kveithola TMFs mainly consist of an alternation of rapidly deposited glacigenic debris flows during glacial maxima and a sequence of well-layered plumites and hemipelagic sediments, which were mainly deposited during the deglaciation phase of the adjacent glacial trough. We have identified eight units above regional reflector R1, which indicate that the ice sheet reached the shelf edge within the Storfjorden Trough on at least three occasions during the last ~200 ka. A shallow subsurface unit of glacigenic debris flows suggests that the ice sheet had a short re-advance over the northern and central part of Storfjorden after the Last Glacial Maximum. From stratigraphy, core and literature data, we estimate that ice sheets reached the shelf edge between 19.5 to 22.5 ka, 61 to 65 ka and 135 to 167 ka. [...]This study was funded by the "Ministerio de Economia y Competitividad" through the IPY project DEGLABAR (CTM2010-17386). The author of this Thesis benefits from a four-year FPI fellowship (BES-2011-0436149) from "Ministerio de Economia y Competitividad"Peer Reviewe