The Thutade 37 skarn occurrence is located approximately 8.7 kilometres west-northwest of the Kemess South deposit (094E 094), about 260 kilometres north of the community of Smithers. The occurrence lies within the Omineca-Cassiar mountains at the southern end of the Toodoggone Gold Camp.
The prospect is situated within a Mesozoic volcanic arc assemblage which lies along the eastern margin of the Intermontane Belt, a northwest-trending belt of Paleozoic to Tertiary sediments, volcanics and intrusions bounded to the east by the Omineca Belt and to the west and southwest by the Sustut and Bowser basins.
Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Stuhini Group andesite flows and pyroclastic rocks. Stuhini volcanics have been intruded by the granodiorite to quartz monzonite Black Lake Suite of Early Jurassic age and are in turn unconformably overlain by or faulted against Lower Jurassic calcalkaline volcanics of the Toodoggone Formation (Hazelton Group).
The dominant structures in the area are steeply dipping faults which define a prominent regional northwest structural fabric trending 140 to 170 degrees. In turn, high angle northeast-striking faults (approximately 060 degrees) appear to truncate and displace northwest-striking faults. Collectively these faults form a boundary for variably rotated and tilted blocks underlain by monoclinal strata.
The Thutade Lake area is largely underlain by andesite volcanics and related sediments of the Stuhini Group and small pockets of Asitka Group sediments. The major structures in the area are north-northwest striking faults, such as the Moose Valley fault and the Ingenika fault. Extensive exploration, including diamond drilling, was conducted on the ground around the Thutade 37 prospect between 1970 to 1984; some nine mineral showings were found. The area hosts fault and/or skarn controlled copper, lead, zinc and silver occurrences throughout.
The Thutade 37 skarn prospect is underlain by fine grained to coarse plagioclase and augite porphyritic, grey to greenish grey to maroon andesite, argillite, chert, quartzite, breccia and conglomerate of the Stuhini Group and the Early Jurassic Kemess pluton, a large intrusive body of porphyritic monzonite, quartz monzonite and granodiorite. Several bodies of marble have been mapped along the northeast corner of Thutade Lake belonging to the Asitka Group.
Mineralization consists of narrow stringers of calcsilicates and sphalerite, galena, pyrite and chalcopyrite in a white to brown, cherty limestone. The main area of interest is where a fault in skarn and volcanic rocks is mineralized with galena, sphalerite, pyrite and chalcopyrite. High concentrations of the sulphides were found on the west side of a steeply dipping, north striking cross fault.
Five samples were collected from two trenches. The analytical results from sample TL25, a 70-centimetre chip sample, are 6.5 per cent zinc, 2.51 per cent lead, 0.81 per cent copper and 67.1 grams per tonne silver (Assessment Report 18241). A grab sample of blast material from Trench 3 assayed 0.253 per cent copper, 1.67 per cent lead, 3.47 per cent zinc and 0.99 gram per tonne silver (Assessment Report 18241). Drillhole 84-6 intersected 18.2 metres of locally weak skarn with lead, zinc and silver mineralization, overlying silicified andesites that are intruded by monzonite dikes. The best analytical results from drill core were 0.56 per cent lead, 1.34 per cent zinc, 0.0056 per cent copper and 6.3 grams per tonne silver over 2 metres (Assessment Report 13022).
In 1988, a program of trenching, geological, geochemical, and geophysical surveys was completed on the Thutade Lake claim group on behalf of Hermes Ventures Ltd. Work consisted of geochemical (595 soil, 1 stream sediment, 30 rock), Very Low Frequency electromagnetic (VLF-EM) (51.2 kilometres), magnetometer (50.8 kilometres) and induced polarization (IP) (11.6 kilometres) surveys, and trenching (2 trenches and 8 pits totalling 2000 cubic metres excavated). Six targets were investigated by the 1988 program, of which three show promise of further mineralization. However, it is felt that any further mineralization is of limited extent and most likely sub-economic. No further work on the property is recommended (Assessment Report 18241). Work consisting of geochemical, VLF-EM, magnetometer, IP surveys and trenching was performed.
