Shallow seismic reflection mapping of the Mackenzie Trough, Beaufort Sea, offshore Yukon and Northwest Territories
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Abstract
The Mackenzie Trough is a unique geological feature of the Canadian Beaufort Sea connecting the Mackenzie River Delta to the continental slope. This study utilizes geoscientific interpretation methods applied to seismic reflection data acquired on the Beaufort Shelf between 2006 and 2017 to map four seismic markers observed within the shallow subsurface of the Mackenzie Trough; i.e. the base of the Mackenzie Trough and three other seismic markers located between the latter and the seafloor. Seismic interpretation has produced four time-structure maps and five time-isopach maps that contribute to the existing geological framework in this sector of the Beaufort Sea. The results suggest that the actual morphology of the Mackenzie Trough is inherited from its base. During the Quaternary, terrigenous sediment supply related to glacier advance and retreat gradually and partially filled the trough. Thicker Quaternary deposits are found within a broad U-shaped erosional cut located in the center of the Mackenzie Trough. Time-isopach maps reveal that zones of thicker sediment accumulations have shifted during the Quaternary, moving landward between the Pliocene and the Holocene.