The Saguenay Fjord basin, Canada, has been struck in the last ~400 yrs by catastrophic sedimentation episodes. Thus, this area represents a unique site to study the genesis of modern mass wasting deposits.
Piston cores (5 to 9 m long) and very-high-resolution (Seistec, 3.5 kHz, 0.2 m resolution) seismic profiles have been collected in the Saguenay Fjord. Geometry of different types of debris flow and turbulent flow deposits have been documented both, on cores and seismic profiles. The 4D evolution of mass wasting deposits have been interpreted by reconstructing the different sedimentation/erosion phases that have led to the sedimentary architecture formation. The deposits evolution has been conducted by correlating scanographic facies and CAT-scan spectral intensities (0.1 mm resolution) with seismic facies. These correlations explain fine-scale changes in seismic facies. The results of this project contribute 1) to resolve mm scale beds that generate the seismic expression of this mass wasting deposits and that cant be resolved by very-high-resolution seismic and 2) to understand the impact of erosion/sedimentation phases that have shaped the sedimentary architecture. Because CAT-scan resolution is four order of magnitude below the seismic resolution, fine-scale architecture derived by CAT-scan can be used to determine very-fine seismic analogs. The comprehension of the multiple phases of erosion and sedimentation that result in the formation of the deposits, becomes essential for the further interpretation of the seismic facies.