General Information
Secondary Commodities: beryl, gemstones
Deposit Type(s): Gemstone
Location(s): 60.192560 N, -131.630130 W
NTS Mapsheet(s): 105B04
Location Comments: Based on location of beryl sample W10 in AR 094348
Hand Samples Available at YGS: No
Capsule
Work History
Staked as Swift 1-8 within a large block of claims in 1978 by the Klinkit Joint Venture (DuPont of Canada Exploration Limited & Duval International Corporation), which explored with geological mapping and contour soil sampling to the north in 1979. The DuPont interest was transferred to CSA Minerals Inc in 1984 and to Goldsearch Inc in 1985. In 1993, H. Kern received a Yukon Mineral Incentives Program (YMIP) grant to explore the area, and prospected and rock sampled that year. I. Elash and Tanana Exploration Inc staked M.C. cl 1-2 (YB93288) in Jul/2001. Elash and Tanana Exploration carried out hand trenching later in the month. The claims were optioned to Strategic Metals Ltd in Aug/2002 which carried out a small hand trenching and prospecting program later in the month. Strategic dropped the option in Nov/2003 and returned the claims to Elash and Tanana Exploration Inc. The claims were optioned to Panarc Resources in 2011, which performed widespread rock sampling of the Seagull Batholith in 2012, although not at the occurrence itself. Panarc Resources staked numerous claim blocks in the area and optioned them to Ucore Rare Metals. In 2014, Ucore flew a large airborne radiometric and magnetic survey over the region, covering almost the entire mapped extent of the Seagull Batholith.
Capsule Geology
This occurrence lies within a belt of Yukon-Tanana Terrane rocks. This belt of rocks is part of an accreted island arc assemblage consisting of biomodal volcanics, coeval plutons and sedimentary rocks, as well as younger Jurassic intrusive rocks and overlap assemblages and Cretaceous intrusions. The occurrence is hosted in mid-Cretaceous Seagull Batholith quartz monzonite.
The occurrence area has predominantly been explored for gem-quality beryl, but exploration in 1993 returned a gold-in-soil value of 288 ppb Au and a rock sample value of 202 ppb Au, 260 m north of the occurrence. However, the author of the report concluded that the anomalies were caused either by small grains of placer gold or by contamination in the laboratory because there were no associated elements in the assay results.
Hand trenching conducted by Elash and Tanana Exploration in 2001 exposed a 20 m section of strongly clay and epidote altered granite containing a partially exposed lens of aggregate intergrown beryl crystals in a saddle between two ridges. Strategic Metals extended the original trench and effectively excavated the beryl lens which measures approximately 80 by 50 by 40 cm in size. An additional lens was exposed 5 m to the south.
The beryl mineralization appears to be associated with multiple acute fault structures that also contain clear quartz flooding and veining. Most of the beryl extracted consists of clear, milky white or pale blue crystal aggregates. Some crystals are up to 7 cm long and 3 cm in diameter, however very few could be segregated without severe damage.
Strategic dug two additional trenches, one on either side of the main trench. The westerly trench encountered beryl float in the upper part of the talus profile but this is believed to be float dispersed down hill from the main showing. Prospecting further along strike to the west uncovered a small amount of beryl float which is also believed to originate from the main showing. No mineralization was found in the easterly trench. South of the main trench prospecting uncovered quartz vein float and float trains which measure up to 25 cm wide and contain 2 to 15 cm vugs and cavities hosting perfectly terminated clear to white quartz crystals and rarer green and purple crystalline fluorite. Strategic Metals felt that since the beryl was hosted within the granite and not on the outer edge where beryllium rich fluids can react with metasedimentary and metavolcanic wall rocks and scavenge sufficient chromium or vanadium, the claims held little potential for emerald mineralization.
Staked as Swift 1-8 within a large block of claims in 1978 by the Klinkit Joint Venture (DuPont of Canada Exploration Limited & Duval International Corporation), which explored with geological mapping and contour soil sampling to the north in 1979. The DuPont interest was transferred to CSA Minerals Inc in 1984 and to Goldsearch Inc in 1985. In 1993, H. Kern received a Yukon Mineral Incentives Program (YMIP) grant to explore the area, and prospected and rock sampled that year. I. Elash and Tanana Exploration Inc staked M.C. cl 1-2 (YB93288) in Jul/2001. Elash and Tanana Exploration carried out hand trenching later in the month. The claims were optioned to Strategic Metals Ltd in Aug/2002 which carried out a small hand trenching and prospecting program later in the month. Strategic dropped the option in Nov/2003 and returned the claims to Elash and Tanana Exploration Inc. The claims were optioned to Panarc Resources in 2011, which performed widespread rock sampling of the Seagull Batholith in 2012, although not at the occurrence itself. Panarc Resources staked numerous claim blocks in the area and optioned them to Ucore Rare Metals. In 2014, Ucore flew a large airborne radiometric and magnetic survey over the region, covering almost the entire mapped extent of the Seagull Batholith.
Capsule Geology
This occurrence lies within a belt of Yukon-Tanana Terrane rocks. This belt of rocks is part of an accreted island arc assemblage consisting of biomodal volcanics, coeval plutons and sedimentary rocks, as well as younger Jurassic intrusive rocks and overlap assemblages and Cretaceous intrusions. The occurrence is hosted in mid-Cretaceous Seagull Batholith quartz monzonite.
The occurrence area has predominantly been explored for gem-quality beryl, but exploration in 1993 returned a gold-in-soil value of 288 ppb Au and a rock sample value of 202 ppb Au, 260 m north of the occurrence. However, the author of the report concluded that the anomalies were caused either by small grains of placer gold or by contamination in the laboratory because there were no associated elements in the assay results.
Hand trenching conducted by Elash and Tanana Exploration in 2001 exposed a 20 m section of strongly clay and epidote altered granite containing a partially exposed lens of aggregate intergrown beryl crystals in a saddle between two ridges. Strategic Metals extended the original trench and effectively excavated the beryl lens which measures approximately 80 by 50 by 40 cm in size. An additional lens was exposed 5 m to the south.
The beryl mineralization appears to be associated with multiple acute fault structures that also contain clear quartz flooding and veining. Most of the beryl extracted consists of clear, milky white or pale blue crystal aggregates. Some crystals are up to 7 cm long and 3 cm in diameter, however very few could be segregated without severe damage.
Strategic dug two additional trenches, one on either side of the main trench. The westerly trench encountered beryl float in the upper part of the talus profile but this is believed to be float dispersed down hill from the main showing. Prospecting further along strike to the west uncovered a small amount of beryl float which is also believed to originate from the main showing. No mineralization was found in the easterly trench. South of the main trench prospecting uncovered quartz vein float and float trains which measure up to 25 cm wide and contain 2 to 15 cm vugs and cavities hosting perfectly terminated clear to white quartz crystals and rarer green and purple crystalline fluorite. Strategic Metals felt that since the beryl was hosted within the granite and not on the outer edge where beryllium rich fluids can react with metasedimentary and metavolcanic wall rocks and scavenge sufficient chromium or vanadium, the claims held little potential for emerald mineralization.
Location Map
Last Updated: Jun 4, 2020
Work History
Year | Work Type | Comment |
---|---|---|
2014 | Airborne Geophysics: Magnetic | |
2014 | Airborne Geophysics: Radiometric | |
2002 | Other: Prospecting | |
2002 | Trenching: Hand | |
2001 | Trenching: Hand | |
1993 | Geochemistry: Rock | |
1979 | Geochemistry: Soil | contour soil sampling to the north |
1979 | Geology: Bedrock Mapping | mapping to the north |
1978 | Other | staked |
Regional Geology - Terrane
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Regional Geology - Bedrock
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Terrane:
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Age Max: MA
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Age Min: MA
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Related References
Number | Title | Page(s) | Document Type |
---|---|---|---|
2004-2 | Bedrock Geology, Dorsey Lake (NTS 105B/4), southern Yukon (1:50,000 scale) | Open File (Geological - Bedrock) | |
YEG1999_11 | Wolf Lake project: Revision mapping of Dorsey Terrane assemblages in the upper Swift River area, southern Yukon and northern B.C. | Annual Report Paper | |
93-043 | Report on Prospecting Work in the Dorsey Lake Area | YMEP Report |
Citations |
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