The CTV T-5 is an occurrence of minor barite-zinc mineralization, 10 kilometres southeast of Mount Mary Henry on the eastern edge of the mountainous Muskwa Ranges of the Northern Rocky Mountains, 31 kilometres south-southeast of the settlement of Summit Lake on the Alaska Highway (Assessment Report 4300, Map 2).
The CTV T-5 is one of a number of similar MINFILE occurrences lying along a narrow, north-northwest trending belt of mainly Devonian sedimentary rocks. The rocks in this 50-kilometres long, 3-kilometres wide belt are bounded to the west by a steeply west-dipping reverse fault which 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 these rocks belong to Ancestral North America (Geological Survey of Canada Map 1713A).
The Devonian rocks in this belt generally dip steeply eastward. 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 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 Dunedin and, very locally, Stone formations (Assessment Reports 4300, 9202). The CTV T-5 actually occurs at the contact between these units, where a lens of barite measuring 4.5 metres in thickness and 30 to 45 metres along strike, contains patches of fine-grained, dark brown sphalerite (Assessment Report 4300). The sphalerite forms up to 20 to 30 per cent of the rock in these zones. Galena is apparently associated (shown as "Pb" on Map 2, Assessment Report 4300).
