The CTV T-7 is an occurrence of minor barite-lead-zinc mineralization on the edge of the mountainous Muskwa Ranges of the Northern Rocky Mountains, 20 kilometres north of the Tuchodi Lakes and 33 kilometres south-southeast of the settlement of Summit Lake on the Alaska Highway (Assessment Report 4300, Map 2).
The CTV T-7 is one of a number of similar MINFILE occurrences laying along a narrow, north-northwest trending belt of mainly Devonian sedimentary rocks. The rocks in this 50-kilometre long, 3-kilometre-wide belt are bounded to the west by a steeply west-dipping reverse fault that juxtaposes mostly Middle Proterozoic and Lower Paleozoic rocks. To the east, the belt is flanked by moderately folded, mainly Mesozoic rocks forming the more subdued Rocky Mountain Foothills. All of these units belong to Ancestral North America (Geological Survey of Canada Map 1713A).
The Devonian rocks in this belt generally dip steeply to the east-northeast. The most important units are the Middle Devonian Stone and Dunedin formations (Geological Survey of Canada Map 1343A, Memoir 373; Assessment Report 4300). The Stone Formation consists of pale grey, fine-grained, thick-bedded dolostone, dolomitic breccia and dolomitic quartz sandstone. The overlying Dunedin Formation comprises grey, well-bedded, fine-grained limestone, with minor dolostone and siliceous lithologies. Other units in the area include the underlying Silurian to Lower Devonian Nonda, Muncho-McConnell and Wokkpash formations, and the overlying Middle Devonian to Mississippian Besa River Formation.
In the early 1970s and again in the early 1980s, the belt was staked to investigate widespread stratabound barite associated with lead-zinc mineralization in the Stone and, mainly, Dunedin formations (Assessment Reports 4300, 9202). The CTV T-7 showing is associated with a pod or lens of banded barite in Dunedin Formation limestone, approximately 120 metres stratigraphically above the contact with the Stone Formation. The barite lens is 30 to 60 centimetres thick and extends for 6 metres along strike (about 350 degrees). Adjacent to it are 2.5- to 5-centimetre-thick bands of disseminated galena and sphalerite, associated with minor fluorite.
Later work consisted of further geochemical sampling of the area (Assessment Report 9202). Two grab samples were taken on a creek a few hundred metres immediately north of the CTV T-7 showing (then part of the Rep claim group), although it is not clear if they were bedrock samples. One grab sample assayed 5.06 per cent zinc with 0.012 per cent cadmium, and the other 0.23 per cent zinc and 0.002 per cent cadmium (Assessment Report 9202, page 11). Grab sample 80ZBT7 yielded 10.01 per cent zinc, 38.6 per cent lead and 70.29 grams per ton silver (Assessment Report 9202).
