Work History
Discovered in 1946 and staked within a large block of Bar claims (#1 = 63692) in Oct/52 by Hudson Bay Mining & Smelting, which carried out geological mapping, trenching and geophysical surveying in 1953 and drilled 3 holes (291.7 m) in 1954.
Restaked in Jul/66 as Dan claims (#1 = Y13401) by W. McKinnon, who optioned them to Boswell River Mines Ltd. The company carried out I.P., resistivity and EM geophysical surveys, soil and silt sampling and hand trenching between 1966 and early 1968, followed by extensive bulldozer trenching in 1968-69. In 1970 the company drilled 9 diamond drill holes (585.5 m) and carried out an aeromagnetic survey over the property.
Restaked as Ed cl (Y83097) in Jul/74 by B. Poulin; as Dave cl (Y93581) in Aug/75 by E. Pallard; as Com cl (YA44800) in Jul/79 by the Wolf Lake Project (Comaplex Resources International Ltd and Dayton Creek Silver Mines Ltd); as Sing cl 1-8 (YA55600) in Jul/80 by A. Mercier; and as Red cl 1-8 (YA68753) in Aug/82 by P. Wilman. Flame Petro-Minerals Corporation tied on Fall cl 1-39 & Park cl 1-32 (YA69156) to the southwest and southeast in Oct/82 and transferred them to W.E. England Drilling Company Ltd in 1983.
The showing was restaked as Best cl 1-8 (YA70336) in Aug/83 by H. Hibbing and as Park cl 1-64 (YB9516) in Nov/87 by First Yukon Silver Resources Inc, which carried out trenching in 1988. D. Schellenberg tied on Dan cl 1-122 (YB14428) to the south in Jul/88 and M cl 15-18 (YB15735) to the north in Jun/89, which were subsequently transferred to First Yukon Silver Resources. First Yukon Silver carried out extensive bulldozer and excavator trenching in 1989, 1990 and 1991. T. Liverton mapped the main showing area in detail in 1990. Cominco Ltd optioned the property and conducted a program of linecutting, trenching and drilled 8 diamond drill holes (1 581 m) on the Park and Key claims in Jul/93, before dropping the option in Dec/93.
In Apr/97, Birch Mountain Resources Ltd acquired an option to earn 100% interest in the property (this occurrence and Minfile Occurrence #105B 026) from First Yukon Silver Resources Inc. The company carried out geological mapping, excavator trenching, geochemical sampling, magnetic and EM geophysical surveying and drilled 6 diamond drill holes (683.15m) later that year. In Mar/99 the company dropped its option on the property and returned the claims to Yukon First Silver. In Aug/99 the main showing was mapped in detail. Detailed mapping continued in 2000.
First Yukon Silver Resources optioned the entire Swift River property in Nov/2004 to Expatriate Resources Ltd in return for Expatriate paying cash in lieu of assessment work and granting First Yukon Silver a 1% net smelter return. In Dec/2004 Expatriate shareholders approved a plan of arrangement whereby most of Expatriate Resources non-Finlayson Lake district exploration properties were transferred to a new company, Pacificia Resources Ltd. The Swift River Property remained with Expatriate Resources, which changed its name to Yukon Zinc Corporation.
Capsule Geology
The area is located 20 km north of the Yukon-British Columbia border, northeast of Swift River, Yukon and has been re-mapped by the Ancient Pacific Margin NATMAP Project (Roots et al., 2004). The occurrence lies between the Cretaceous Seagull Batholith and less than 2 km southwest of the Cassiar Batholith, in rocks of the Ram Creek assemblage (mainly Mississippian age). Roots et al., (2000) have assigned the Ram Creek assemblage to the Yukon-Tanana terrane. The Ram Creek assemblage appears to be composed of structurally interleaved slices of siliciclastic and green metasedimentary layers, marble and calc-silicate rocks . All rocks have been deformed and metamorphosed to upper green schist facies during mid-Mississippian to Permian time. About 2 km south of the occurrence is a high ridge underlain by a steep-dipping diorite sill about 1 kilometre thick, and inferred to be of Jurassic age.
Irregular layers of black sphalerite and pyrrhotite occur with garnet-diopside skarn along the sheared contact between banded quartz-actinolite-chlorite meta-tuff and underlying marble. Stripping in the main showing area has exposed sulphide mineralization over a strike length of 315 m.
Up to 3 individual sulphide layers, each averaging about 1.5 m thick occur over a width of 50 m, and disseminated sulphides occur in calc-silicate rocks between the massive sulphide layers. Although the massive sulphide layers appear to be roughly concordant, detailed mapping by Liverton indicated that they follow a branching system of south-dipping reverse faults and minor cross faults. Polished thin sections show that the sulphides were introduced along with actinolite and chlorite during retrograde alteration of the primary skarn minerals. Mineralization is layered, parallel to regional stratigraphy but locally cross-cuts minor folds. Bands of disseminated sphalerite in the lower marble layer assayed low grades of zinc over significant widths.
The original showing drilled by Hudson's Bay lies uphill, approximately 100 m south of the First Yukon Silver trenching. It consists of a 12 x 1.7 m exposure of massive pyrrhotite and sphalerite in actinolite-bearing meta-tuff which strikes northwest and dips about 70 southwest. This mineralization appears to correlate with the uppermost sulphide layer exposed in the First Yukon Silver excavation. Samples taken by P. Sevensma for Boswell River Mines in 1962 and 1966 averaged 8.0% Zn over 1.7 m.
Magnetic surveys carried out by Boswell River Mines indicate that the mineralization is traceable eastward beneath 1.5 to 15 m of glacial overburden which has masked soil geochemical response in the area. Sevensma reported massive pyrrhotite float 213 m east-southeast of the original showing which assayed 3.2% Zn, 0.25% Pb and 25.7g/t Ag. Along strike to the west, strong zinc soil anomalies extend westwards towards the Crescent Lake showings (Minfile Occurrences #105B 026A, B, and C).
A chip sample collected over the main showing by Noranda during a property visit in 1990 averaged 2.5% Zn over 6 m. A chip sample collected in 1990 by T. Bremner, a geologist employed by the Department of Indian and Northern Affairs, across the lowest of three massive sulphide layers averaged 5.6% Zn over 1.0 m. Specimens collected by Placer Dome during another property visit in the same year returned up to 39.35% Zn, with some samples containing anomalous levels of gold, antimony, silver, lead and copper. For example, a specimen of banded pyrite and sphalerite from the middle of the main trench contained 205 ppb Au, 83.0 g/t Ag, 1 050 ppm Pb and 8.74% Zn (Yukon Exploration 1990, p. 29).
Only 1 of Cominco¿s drill holes tested the main showing. The remaining 7 holes tested showings located to the west on Minfile Occurrences #105B 026A, B, C). Cominco did not file assay results but the single hole appears to have intersected mostly calc-silicate skarn and biotite hornfels with occasional thin lenses of mudstone/siltstone and volcanic material.
Birch Mountain Resources resampled and remapped all of the known showings with the aim of identifying new areas of potential mineralization. The geophysics program was geared towards trying to locate and extend the strike of known mineralized horizons located across the width of the claim block. Six of the drill holes were collared on the Dan, and neighboring Lucy and Lost showings. Hole SR 97-06 collared on the Dan occurrence (this occurrence) returned 14.57% Zn over 1.2 m and 6.55% Zn over 1.88 m Birch Mountain reinterpreted the numerous showings as boudins of previously continuous strata-bound sulfide beds occurring at a number of stratigraphic horizons and suggested a syn-sedimentary exhalative origin for the mineralization.
Detailed mapping by de Silva et al., in 1999 and 2000 reinterpreted the finely-banded siliceous rock units at the occurrence as a rhyolite and the cherty layers as exhalites. This led to the theory that mineralization previously described as being skarn due to the pyroxene-amphibole-garnet silicate mineral assemblages were in fact stratabound massive sulphide type (VMS). This theory was expanded to explain mineralization at neighboring occurrences. First Yukon Silver believes that the greatest potential for additional mineralization lies to the south.
The origin of the mineralization was debated in the 1990s. The mineralogy is clearly skarn-type, and mineralization postdates metamorphic layering. It has been argued that the sulphides have been remobilized from a pre-existing syngenetic deposit. The stratabound nature of mineralization and presence of flow-banded siliceous rock interpreted as rhyolite suggest associated volcanism. Birch Mountain and First Yukon Silver pointed out the characteristics of a sedimentary (possibly volcanic) exhalative deposit that had been deformed and subsequently contact-metamorphosed by Jurassic and Cretaceous intrusions.
Four Pb isotope analyses of galena and pyrrhotite collected by Mortensen and Gabites (2002) formed a loose cluster of analyses conforming to a broadly mid-Triassic to mid-Jurassic age. They concluded that mineralization had a temporal and genetic association with Early Jurassic magmatism.
References
ABBOTT, J.G., 1981. Geology of Seagull Tin District. Yukon Geology and Exploration 1979-80, p. 32-44.
BIRCH MOUNTAIN RESOURCES LTD, Nov/97. Assessment Report #093884 by S.P. Santiago and V. Pratico.
BIRCH MOUNTAIN RESOURCES LTD, Jun/97. Assessment Report #093886 by A. Mann.
BIRCH MOUNTAIN RESOURCES LTD, Sep/98. Assessment Report #093904 by G. DePaoli.
BIRCH MOUNTAIN RESOURCES LTD, News Release, 15 Apr/97; 10 Sep/97; 25 Sep/97; 18 Nov/97; 11 Mar/99.
BOSWELL RIVER MINES LTD, Nov/66. Prospectus Report #018616 by P.H. Sevensma.
BOSWELL RIVER MINES LTD, Jul/67. Assessment Report #060682 (Geophysical Report) by P.H. Sevensma.
BOSWELL RIVER MINES LTD, 1968. Assessment Report *#018617 by P.E. Walcott.
BOSWELL RIVER MINES LTD, Aug/71. Assessment Report #060879 by H. Wober.
D¿EL REY SILVA, L.J.H. et al., 2001. A structural analysis of the upper Swift River area (105B\3), Yukon. Part 1: Dan Zn occurrence and implications for sulfide mineralization. In: Yukon Exploration and Geology 2000, D.S. Emond and L.H. Weston (eds.), Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, p.289-300.
FIRST YUKON SILVER RESOURCES INC, Mar/89. Assessment Report *#092686 by D. Schellenberg.
HARMS T.A. AND STEVENS, R.A. 1995. Investigations in the Dorsey terrane, Part 2: lithologies and structure of (?) Paleozoic stratified rocks in the Stikine Ranges, northern British Columbia; in Current Research 1995-A; Geological Survey of Canada, p. 129-133.
LIVERTON, T. AND BREMNER, T. 1990. The Dan Property. In: Yukon Exploration 1991. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, p. 27-30.
LIVERTON, T. & D¿EL REY SILVA, L.J.H., 2000. Preliminary Structural Analysis of Mineralized units in the Swift River Region. Submitted as Assessment Report #094117.
LIVERTON, T. & D¿EL REY SILVA, L.J.H., Feb/2001. Further structural mapping on the Dan prospect, Upper Swift river (105B/3). Submitted as Assessment Report #094194.
MORTENSEN, J.K. AND GABITES, J. E., 2002. Lead Isotopes constraints on the metallogeny of southern Wolf Lake, southeastern Teslin and Northern Jennings river map areas, Yukon and British Columbia: Preliminary results. In: Yukon Exploration and Geology 2001, D.S. Emond, L.H. Weston and L.L. Lewis (eds.), Exploration and Geological Services Division, Yukon region, Indian and Northern Affairs Canada, p. 179-188.
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NORTHERN MINER, 1 Jan/90; 13 Oct/97; 8 Dec/97.
ROOTS, C.F., DE KEIJZER, M. And NELSON, J.L., 2000. Revision mapping of Dorsey Terrane assemblages in the upper Swift River area, southern Yukon and northern B.C. In: Yukon Exploration and Geology 2000, D.S. Emond and L.H. Weston (eds.), Exploration and Geological Services Division, Yukon region, Indian and Northern Affairs Canada, p. 115-125.
ROOTS, C., NELSON, J., AND STEVENS, R., 2004. Bedrock Geology, Seagull Creek, Yukon Territory; Geological Survey of Canada, Open File 4632; Yukon Geological Survey, Open File 2004-1, scale 1:50 000.
STEVENS, R.A. AND HARMS, T.A., Investigations in the Dorsey terrane, Part 1: stratigraphy, structure, and metamorphism in the Dorsey Range, southern Yukon Territory and northern British Columbia, in Current Research 1995-A; Geological Survey of Canada, p. 117-127.
YUKON EXPLORATION 1990, p. 27-30; 1991, p. 9, 10.
YUKON EXPLORATION AND GEOLOGY 1997, p. 20, 37-38; 1998, p. 20.
YUKON GEOLOGY AND EXPLORATION 1979-80, p. 144-145.
YUKON MINING AND EXPLORATION OVERVIEW 1989, p. 5,7.
