Tectonic Styles of Northern Yukon Territory and Northwestern District of Mackenzie, Canada1
Published:January 01, 1973
A diversity of tectonic styles is displayed in northern Yukon Territory and northwestern District of Mackenzie. Some tectonic elements of the region, such as the Barn and White uplifts, are basically fault-bounded, ovate domes with cores of Paleozoic and possibly older carbonate and clastic rocks; the domes are separated by structural depressions largely filled with Mesozoic clastic sequences. Other structural elements are elongate and trend parallel or subparallel with one another. Because some elements were tectonically deformed more than once, stacking of styles may be present, as in the Romanzof uplift, where open folds in Carboniferous and Permian carbonate and clastic units lie with profound unconformity on acutely folded, faulted, and cleaved rocks assumed to be no younger than Silurian. Each deformed body served as a platform for the next younger sedimentary succession and possibly acquired cumulative structural features characteristic of the syles of all younger deformations.
The belt of Cretaceous, south-dipping thrust faults on the south flank of Brooks Range in Alaska is comparable in style to that along the eastern margin of the Canadian cordillera at the latitude of the 49th Parallel. The belt continues southeastward into Canada, but the number of faults and the net displacement diminish toward the Barn uplift. Southeast of the Barn uplift, steep faults, some with demonstrable strike slip, become major components of the structural style. The latter faults, active at least locally into the mid-Tertiary, also served to transport differentially the northern Yukon tectonic complex toward the Beaufort shelf and the Canada basin. Beyond this complex, in northwestern District of Mackenzie, is Kugaluk homocline, a gently northwest-dipping layered succession of Tertiary strata flanked on the southeast by Campbell uplift.
Campbell uplift is the northeast continuation of Aklavik arch, a composite structural high comprising individual northeast-trending uplifts arranged en échelon toward the right. The arch complex extends from the northern Yukon to the Beaufort Sea and possibly is continuous with the Minto arch in the Arctic Archipelago. Carbonate accumulations comparable to those seen in the White uplift and its vicinity, or those penetrated by the drill in the northern Eagle basin, may be present beneath suitable caprocks on the flanks of the complex. Such accumulations would greatly enhance the economic prospects of the Mackenzie delta region and the Beaufort shelf.
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Following the discovery of Prudhoe Bay oil field in 1968, much attention was turned to the Arctic in the search for giant hydrocarbon accumulations. The Soviets had already proved giant reserves in their West Siberian Basin, and exploration was moving ahead quickly in the Canadian Arctic. Plans were drawn up for an AAPG Symposium on Arctic Geology and held in February 1971. Papers were selected from the Symposium for this publication and cover seven topical groupings: Regional Arctic Geology of Canada, Regional Arctic Geology of the Nordic Countries, Regional Arctic Geology of the USSR, Regional Arctic Geology of Alaska, Comparisons in the North Atlantic Borders, Evolution of the Arctic Ocean Basin, and Economics of Petroleum Exploration and Production in the Arctic.