Work History
Staked as Viola cl (Y22485) in Dec/67 by Esansee Exploration Ltd and later transferred to Yucan Silver Mines Ltd, which carried out bulldozer trenching in 1968.
Restaked twice by Cypress Exploration Ltd, originally as FXE cl (Y64626) in Aug/72 when it performed minor sampling, and later as FIS cl (Y83111) in Jul/74 when it drilled two holes (38.1 m).
Restaked as JC cl (YA25465) in Aug/77 by the DC Syndicate (Dome and Cominco), which explored with mapping and geochem sampling in 1978-80, trenching in 1978, mag surveys in 1979-80, 8 holes (804.7 m) in 1979, 14 holes (915.3 m) in 1980, and mapping, an aeromag survey and 9 holes (1673 m) in 1981. In 1982, DC Synd drilled another 8 holes (1527m) on the east end of the zone.
E. Johnson staked Fur cl (YA33778) to the south in Jul/78 and performed prospecting and sampling in 1978 and 1979.
Brett Resources staked Smart, Cass and Seagull cl around original JC occurrence in 2005.
Capsule Geology
Tin-bearing skarn has formed along the contact between a porphyritic lobe of the mid Cretaceous Seagull Batholith and a shallow dipping 30-35 m carbonate layer which occurs in a thick sequence of Mississippian quartzite. The original discovery was a diopside skarn band up to 6 m thick that is exposed for a length of over 850 m. It contains scattered patches of massive pyrrhotite and chalcopyrite up to a metre long and small patches of disseminated magnetite, arsenopyrite, pyrite and pyrrhotite. Surface assays were low and the best core assay was 2.7% Cu and 65.1 g/t Ag across the first 0.9 m of Hole 1 on claim FXE 2. Nickel and gold assays were all trace.
In 1977, DC Syndicate discovered tin mineralization associated with light calc-silicate skarn and dark skarn. The dark variety is composed of pyroxene, epidote, actinolite, garnet and calcite. Mineralization includes sphalerite, chalcopyrite, arsenopyrite, magnetite, scheelite and, locally, axinite, beryl, fluorite and apatite. A pipe-like lens or diatreme of breccia with axinite-fluorite mineralization is also present. Tin mineralization is associated with all types of skarn and consists of cassiterite with lesser amounts of malayaite, stannite and stanniferous tetrahedrite. The only assay reported, which was the best chip sample from the 1978 trenches, is 1.26% Sn, 0.4% Cu, 0.04% Zn and trace WO3 across a true thickness of 2.6 m.
The 1980 and 1981 drilling, which was concentrated at the east end, reportedly defined a significant zone of tin mineralization, although grades generally average less than 0.2% Sn. The 1982 holes encountered structural complications.
Isotopic studies by Layne et al. (1991) clearly indicate a magmatic source for all of the sulphide minerals. Paragenetic and fluid inclusion studies show that cassiterite and fluorite are associated with quartz-biotite skarn formed in a narrow zone along the skarn-granite contact from a pulse of high temperature, high salinity magmatic fluid, during the fourth of six stages of skarn formation.
References
BRETT RESOURCES INC., News Release, 4 Oct/05.
COMINCO LTD, Jun/82. Assessment Report *#091062 by L.J. Nagy.
CYPRESS RESOURCES LTD, Nov/72. Prospectus Report by R.S. Adamson.
CYPRESS RESOURCES LTD, 1974. Assessment Report *#091099 by F. Erl and F. Schomig.
DC SYNDICATE, 1977. Assessment Report *#090354 by J.E. Cartier and J.C. Stephens.
DC SYNDICATE, 1978. Assessment Report *#090462 by J.C. Stephens.
DC SYNDICATE, 1979. Assessment Report *#090567 by J.C. Stephens.
DICK, L.A., 1980. A comparative study of the geology, mineralogy, and conditions of formation of contact metasomatic mineral deposits in the northeastern Canadian Cordillera. Unpublished PhD thesis, Queen's University, p. 8, 9, 165, 194, 205-16, 381, 392.
GEORGE CROSS NEWSLETTER, 10 Oct/74.
JOHNSON, E.H., 1979. Assessment Report *#090524 by E.H. Johnson.
LAYNE, G.D. ET AL., 1991. The JC tin skarn deposit, Southern Yukon Territory. Economic Geology, Vol 86, p. 29-65.
MINERAL INDUSTRY REPORT, 1978, p. 57.
WESTERN MINER, Apr/80, p. 45-48.
YUKON GEOLOGY AND EXPLORATION 1979-80, p. 148-149.
YUKON EXPLORATION AND GEOLOGY 1981, p. 98; 1982, p. 97; 1983, p. 28-29.
