Mineral Possibilities of Areas Adjacent to the Alaska Highway (ff91bb7d-99bb-4806-86e2-a2d9cfd3ea8e)

Apart from a few sketches and incomplete maps, mainly topographical, and one or two detailed maps of placer-creeks, there is little information on the topography and geology of most of the country adjacent to the sections of the Alaska Highway in the Liard River area, particularly that part east of Kechika river. In 1943, the Geological Survey of Canada made a recon-naissance from Fort Nelson clown the river of that name to the Liard, thence up the latter to Hell Gate, and also up Beaver river for a distance of fifty miles. The whole of the area covered was found to be underlain by sedimentary rocks, not a single igneous dyke being seen. The British Columbia Department of Mines began reconnaissances near the highway both in and north of the drainage basin of Prophet and Muskwa rivers with a view to finding structures favourable for the accumulation of oil. In Liard River valley near the mouth of Smith river and at intervals from there clown to Devil' s Portage occur warm springs whose character and origin are not definitely' known, since they have not been investigated (21, p. 38A). Similar springs are said to occur at several localities over a broad belt extending from Muskwa river across the Liard to the Nahanni River country (26, p. 11). On Liard river below the mouth of Dease river, stratified sands, gravels, and clays of Pleistocene (?) age are constantly met with and in one or two places are underlain by sandy clays. The distribution of the latter, however, is very limited in the section cut by the river west of the Rocky mountains. The only range of these mountains that reaches the Liard is the high limestone ridge which approaches the mouth of Vents river from the southeast and then almost vanishes a few miles to the northwest of it (27, pp. 43-45). In general, the ranges of the Rockies in the area under consideration have been but little explored, but they are undoubtedly very largely sedimentary and, with the exception of some volcanics and intrusives on their western flanks, are probably almost entirely so. Unlike the high, deeply incised ranges in southern British Columbia, they dwindle in elevation north of Terminus mountain to low-wooded ridges separated by wide swampy valleys, and practically lose their identity between it and the Liard. The foothills, which, along the Liard, have a width of 38 miles (from near the mouth of Trout river to Hell Gate) are composed of a great series of alternating shales and sandstones, with some limestones, all folded closely together, which resemble those found in the foothills farther south (27, pp. 50, 19-20).