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Beaufort-Mackenzie Basin

| Liard Basin | Kandik Basin | Bonnet Plume Basin | Old Crow Basin | Whitehorse Trough | Peel Plateau and Plain | Eagle Plain Basin | Beaufort-Mackenzie Basin |

Photo: Devon Canada


The Beaufort-Mackenzie basin of northern Yukon is an Arctic margin basin underlain by complexly faulted and folded Proterozoic through Tertiary sediments. The area is flanked to the south by exposed Proterozoic and Lower Paleozoic sediments of the British Mountains and Richardson Mountains. It contains four tectono-stratigraphic assemblages separated by major regional unconformities: a lowermost Proterozoic clastic assemblage forming the economic basement, Lower Paleozoic sedimentary rocks delineating a carbonate platform to marine basin transition with dominantly basinal shales in the area of interest, Carboniferous to Lower Cretaceous non-marine clastic sedimentary rocks transitioning to shallow marine and intertidal deposits, and Lower Cretaceous to Tertiary northward prograding delta deposits. Upper Cretaceous sedimentary rocks include foreland flysch deposits from extensively eroding uplands of the Cordilleran orogen.

The dominant structural fabric is related to Cretaceous-Tertiary contractional deformation of the Cordilleran fold belt during the Cordilleran orogeny. Structures form an arcuate trend with east to southeast strikes in northwestern Yukon rotating to a north-south trend in eastern Yukon. Tight folds, thrust faults, strike-slip faults, and extensional faults all formed as part of this deformation. Earlier deformation features related to the Ellesmerian orogeny and Jurassic-Cretaceous extension are locally discernable through the later overprinting.