Unnamed (near upper Martha Creek)

Site Name

Primary: Unnamed (near upper Martha Creek)

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Commodity

Primary: Tungsten
Primary: Lead
Primary: Bismuth
Primary: Tin
Primary: Antimony
Primary: Silver
Secondary: Beryllium
Secondary: Boron-Borates
Secondary: Molybdenum

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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: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant:

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Physiography

Not available

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Mineral Deposit Model

Model Name: Polymetallic veins

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: Tourmalinization?

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Rocks

Not available

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Analytical Data

Not available

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Materials

Gangue: Tourmaline
Gangue: Quartz

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Comments

Comment (Deposit): Model Name = Polymetallic, sulfide-bearing vein in amphibolite facies metasedimentary rocks.

Comment (Geology): Geologic Description = Sulfide-bearing rocks occur on a northwest-striking fault ,which cuts quartz-graphite-biotite gneiss, at the contact of the gneiss with a gneissic marble layer. The occurrence is about 2.4 miles upstream from weakly mineralized quartz-breccia zones exposed along lower Martha Creek (NM005) and 2 miles northwest of the fluorite pipe in 'Fluorite Creek' (a local name assigned by Sainsbury, Smith, and Kachadoorian, 1970; NM010). The occurrences are generally in an area of small tourmalinized granite plugs of Cretaceous age. At this locality, Smith (in Sainsbury, Smith, and Kachadoorian, 1972) collected a sulfide-bearing rock sample (67Ats118) that contained 30 ppm silver, 15,000 ppm boron, 5,000 ppm bismuth, 7 ppm beryllium, 70 ppm molybdenum, 10,000 ppm lead, 1,500 ppm antimony, 300 ppm tin and 500 ppm tungsten. The presence of elevated boron values suggests that the rocks are tourmalinized. The area is underlain by amphibolite facies graphitic metasedimentary rocks that are locally gneissic. Sainsbury, Smith and Kachadoorian (1972) mapped granite stocks and felsic dikes in the Martha Creek drainage including several that are toumalinized. The amphibolite facies metasedimentary rocks are now considered to have a late Proterozoic or early Paleozoic protolith (Till and Dumoulin, 1994; Hannula and others, 1995), perhaps correlative with parts of the Nome Group. Like the Nome Group, these rocks probably 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 (Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson and Arth, 1983; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998).

Comment (Workings): Workings / Exploration = The occurrence is a surface exposure of sulfide-bearing rock.

Comment (Reference): Primary Reference = Sainsbury, Smith, and Kachadoorian, 1972

Comment (Exploration): Status = Probably inactive

Comment (Geology): Age = Cretaceous; post mid-Cretaceous amphibolite facies metamorphism and possibly the same age as mineralized Cretaceous granitic rocks in the area.

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References

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): 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): 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): 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): 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): Sainsbury, C.L., Smith, T.E., and Kachadoorian, Reuben, 1972, Reconnaissance geologic map of the Nome D-3 quadrangle, Alaska: U.S. Geological Survey Open-File Report 72-327, 14 p., 1 sheet, scale 1:63,360.

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): 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): 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): 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): 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): 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): 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): 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): 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.

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