Sliscovich

Site Name

Primary: Sliscovich

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Commodity

Primary: Gold
Primary: Antimony
Secondary: Silver
Secondary: Arsenic

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Location

State: Alaska
District: Nome

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant:

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Physiography

Not available

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Mineral Deposit Model

Model Name: Simple Sb (veins, pods, etc)

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Text: Chapin (1914, p. 404) reported that the footwall was strongly bleached for about 15 inches and converted to quartz and sericite with fine-grained white pyrite (arsenopyrite?). The hanging wall was silicified. D. Simpson (Bear Creek Mining Company, written communication, 1984) found that the footwall schist was sheared, and altered and carried small amounts of arsenopyrite.

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Arsenopyrite
Ore: Gold
Ore: Pyrite
Ore: Stibnite
Gangue: Albite
Gangue: Ankerite
Gangue: Quartz

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Comments

Comment (Production): Production Notes = A small ore shipment reported by Chapin (1914) contained about 35 percent antimony; gold and silver were present, but their values were not reported. An 88-ton ore shipment in 1915 returned most of its value in gold (Mertie, 1918 [B 662-I, p. 425-449]). Gold values obtained by Bear Creek Mining locally exceeded 1 ounce per ton. Gamble and others (1985, p. 28) reported that antimony-rich samples contained 4.4 to 6.5 ppm gold, 2 to 7 ppm silver, and 100 to 250 ppm arsenic.

Comment (Deposit): Model Name = Simple Sb deposits and low sulfide, Au-quartz vein? (Cox and Singer, 1986; models 27a and 36a).

Comment (Deposit): Model Number = 27d?, 36a?

Comment (Geology): Geologic Description = At least two distinctive types of mineral deposits occur on the Sliscovich claim block. A vein, probably continuous with mineralization at the Breen East prospect (NM085), strikes about east-west and appears to trend onto the southwest part of the My Best Lode claim, where it was opened by adits and trenches. Farther southwest, stibnite-bearing veins near a contact between metasedimentary schist and marble are subparallel to the alignment of the Sliscovich Discovery claim, and stibnite float is found at or below this contact for the length of the claim. Workings in the northeast part of the Sliscovich Discovery claim are, at least in part, on the contact of metasedimentary schist underlying marble (D. Simpson, Bear Creek Mining Company, written communication, 1984). The contact zone on the Sliscovich Discovery claim was probably developed when the property was visited by Chapin in 1913 (Chapin, 1914, p. 403-404). Chapin described the occurrence as a quartz-stibnite vein that strikes N 60 E and dips 45 degrees northwest. Stibnite was mostly on the footwall, but it also occurred as veins and nests in quartz (Cathcart, 1922). Gouge and slickensides were locally present on both footwall and hanging wall (Mertie, 1918 [B 662-I, p. 425-449]). The vein was developed by a 315-foot adit, a drift on the lode, and an incline from the drift. A 70-foot-long part of the lode was mined for antimony in 1915 from the incline workings. In general, the vein that remained was only a few inches wide, but Cathcart (1922, p. 230) found one section about 45 inches thick that consisted of 13 inches of stibnite and 32 inches of opaque quartz. The vein was similar to that at the Hed & [and] Strand mine (NM070) with most of the quartz on the hanging wall. Massive stibnite-quartz float occurs on the My Best Lode claim and appears to be from the same vein developed on the Breen West claims (NM087). Cathcart (1922) reported some steeply dipping quartz veinlets with northeast strike. A small ore shipment reported by Chapin (1914) contained about 35 percent antimony; gold and silver were present, but their values were not reported. An 88-ton ore shipment in 1915 returned most of its value in gold (Mertie, 1918). Gold values obtained by Bear Creek Mining locally exceeded 1 ounce per ton. Gamble and others (1985, p. 28) reported that antimony-rich samples contained 4.4 to 6.5 ppm gold, 2 to 7 ppm silver, and 100 to 250 ppm arsenic. The Sliscovich mine is in metasedimentary schist near an overlying marble. A granitic orthogniess is mapped upslope to the north (Hummel, 1962 [MF 248]). The metamorphic rocks are part of the Nome Group, which is derived from Proterozoic to early Paleozoic protoliths (Till and Dumoulin, 1994). The Nome Group underwent regional blueschist facies metamorphism in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Armstrong and others, 1986; Hannula and McWilliams, 1995). The blueschist facies rocks were recrystallized to greenschist facies or higher metamorphic grades in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Hudson and Arth, 1983; Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998). Lode gold mineralization on Seward Peninsula is mostly related to the higher temperature metamorphism in the mid-Cretaceous (Apodoca, 1994; Ford, 1993 [thesis]; Ford and Snee, 1996; Goldfarb and others, 1997). The antimony-gold deposits are probably of about the same age.

Comment (Exploration): Status = Active?

Comment (Geology): Age = Mid-Cretaceous; controlled by structures that post-date regional metamorphism; may be same age as some lode gold deposits of Seward Peninsula.

Comment (Reference): Primary Reference = Chapin, 1914

Comment (Workings): Workings / Exploration = The claims of the Sliscovich group were located between June 20, 1907, and January 1, 1917, and were patented to James F. Halpin in 1924. According to Chapin (1914, p. 403-404), at least one claim was located as early as 1905. The Sliscovich Discovery claim was developed by 315-foot adit and an incline driven 100 feet along the vein. Stibnite was mined from a 70-foot-long stope. These workings were driven in 1915 or before. The My Best Lode claim also has mine workings. The area was explored by Mapco in about 1981-82. The Sliscovich claims were mapped during Bear Creek Mining's option of the Breen claims (D. Simpson, written communication, 1984). Subsequently the area was studied by BHP (Ford, 1993 [thesis]). The area is within an extensive east-west, gold and arsenic soil anomaly identified by BHP.

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References

Reference (Deposit): Bundtzen, T.K., Reger, R.D., Laird, G.M., Pinney, D.S., Clautice, K.H., Liss, S.A., and Cruse, G.R., 1994, Progress report on the geology and mineral resources of the Nome mining district: Alaska Division of Geological and Geophysical Surveys, Public Data-File 94-39, 21 p., 2 sheets, scale 1:63,360.

Reference (Deposit): Amato, J.M., and Wright, J.E., 1998, Geochronologic investigations of magmatism and metamorphism within the Kigluaik Mountains gneiss dome, Seward Peninsula, Alaska, in Clough, J.G., and Larson, Frank, eds., Short Notes on Alaskan Geology 1997: Alaska Division of Geological and Geophysical Surveys Professional Report 118a, p. 1-21.

Reference (Deposit): Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, 482 p.

Reference (Deposit): Amato, J.M., and Wright, J.E., 1997, Potassic mafic magmatism in the Kigluaik gneiss dome, northern Alaska -- A geochemical study of arc magmatism in an extensional tectonic setting: Journal of Geophysical Research, v. B102, no. 4, p. 8065-8084.

Reference (Deposit): Ford, R.C., and Snee, L.W., 1996, 40Ar/39Ar thermochronology of white mica from the Nome district, Alaska: The first ages of lode sources to placer gold deposits in the Seward Peninsula: Economic Geology, v. 91, p. 213-220.

Reference (Deposit): Hannula, K.A., Miller, E.L., Dumitru, T.A., Lee, Jeffrey, and Rubin, C.M., 1995, Structural and metamorphic relations in the southwest Seward Peninsula, Alaska; Crustal extension and the unroofing of blueschists: Geological Society of America Bulletin, v. 107, p. 536-553.

Reference (Deposit): Hannula, K.A., and McWilliams, M.O., 1995, Reconsideration of the age of blueschist facies metamorphism on the Seward Peninusla, Alaska, based on phengite 40Ar/39Ar results: Journal of Metamorphic Geology, v. 13, p. 125-139.

Reference (Deposit): Amato, J.M., Wright, J.E., Gans, P.B., and Miller, E.L., 1994, Magmatically induced metamorphism and deformation in the Kigluaik gneiss dome, Seward Peninsula, Alaska: Tectonics, v. 13, p. 515-527.

Reference (Deposit): Dumitru, T.A., Miller, E.L., O'Sullivan, P.B., Amato, J.M., Hannula, K.A., Calvert, A.T., and Gans, P.B., 1995, Cretaceous to Recent extension in the Bering Strait region, Alaska: Tectonics, v. 14, p. 549-563.

Reference (Deposit): Ford, R.C., 1993, Geology, geochemistry, and age of gold lodes at Bluff and Mt. Distin, Seward Peninsula, Alaska: Golden, Colorado School of Mines, Ph.D. dissertation, 302 p.

Reference (Deposit): Apodoca, L. E., 1994, Genesis of lode gold deposits of the Rock Creek area, Nome mining district, Seward Peninsula, Alaska: Boulder, Colorado, University of Colorado, Ph.D. dissertation, 208 p.

Reference (Deposit): Hudson, T.L. 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America, The Geology of North America, v. G-1, p. 657-670.

Reference (Deposit): Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, The Geology of North America, DNAG, v. G-1, p. 141-152.

Reference (Deposit): Forbes, R.B., Evans, B.W., and Thurston, S.P., 1984, Regional progressive high-pressure metamorphism, Seward Peninsula, Alaska: Journal of Metamorphic Geology, v. 2, p. 43-54.

Reference (Deposit): Thurston, S.P., 1985, Structure, petrology, and metamorphic history of the Nome Group blueschist terrane, Salmon Lake area, Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 96, p. 600-617.

Reference (Deposit): Gamble, B.M., Ashley, R.P., and Pickthorn, W.J., 1985, Preliminary study of lode gold deposits, Seward Peninsula, in Bartsch-Winkler, Susan, ed., The United States Geological Survey in Alaska, Accomplishments during 1984: U.S. Geological Survey Circular 967, p. 27-29.

Reference (Deposit): Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska: Geology, v. 20, p. 487-490.

Reference (Deposit): Miller, E.L., and Hudson, T.L., 1991, Mid-Cretaceous extensional fragmentation of a Jurassic-Early Cretaceous compressional orogen, Alaska: Tectonics, v. 10, p. 781-796.

Reference (Deposit): Armstrong, R.L., Harakal, J.E., Forbes, R.B., Evans, B.W., and Thurston, S.P., 1986, Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and southern Brooks Range, Alaska, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 184-203.

Reference (Deposit): Hudson, T.L., and Arth, J. G., 1983, Tin-granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.

Reference (Deposit): Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Nome quadrangle, Alaska: U.S. Geological Survey Open-File report 78-93, 213 p.

Reference (Deposit): Hummel, C.L., 1962, Preliminary geologic map of the Nome D-1 quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-248, 1 sheet, scale 1:63,360.

Reference (Deposit): Cathcart, S.H., 1922, Metalliferous lodes in southern Seward Peninsula: U.S. Geological Survey Bulletin 722, p. 163-261.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Nome quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-463, 2 sheets, scale 1:250,000.

Reference (Deposit): Sainsbury, C.L., Coleman, R.G., and Kachadoorian, Reuben, 1970, Blueschist and related greenschist faces rocks of the Seward Peninsula, Alaska, in Geological Survey research 1970: U.S. Geological Survey Professional Paper 700-B, p. B33-B42.

Reference (Deposit): Chapin, Theodore, 1914, Placer mining on Seward Peninsula: U.S. Geological Survey Bulletin 592-L, p. 385-395.

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