Mespelt

Site Name

Primary: Mespelt

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Commodity

Primary: Uranium
Primary: Silver
Primary: Lead
Secondary: Zinc
Secondary: Tungsten
Secondary: Gold
Secondary: Tin

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Location

State: Alaska
District: McGrath

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

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Physiography

Not available

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Mineral Deposit Model

Model Name: Sn 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: Greisen assemblages of quartz-tourmaline-muscovite-chlorite are developed locally (C.C. Hawley and Associates, Inc. 1978).

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Zeunerite
Ore: Metazeunerite
Ore: Sphalerite
Ore: Pyrite
Ore: Galena
Gangue: Siderite
Gangue: Quartz
Gangue: Limonite
Gangue: Calcite

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Comments

Comment (Geology): Age = Tertiary; mineralization in the Boulder Creek, Jiles-Knudson , Hogback and Mespelt areas is interpreted to be linked to the Tonzona granite (Tmt), part of the McKinley Sequence, that has been determined to range from 52.3 to 56.2 m.y. in age (Reed and Lanphere, 1972; Reed and Nelson, 1980).

Comment (Production): Production Notes = No published information available.

Comment (Reference): Primary Reference = Maloney and Thomas, 1966

Comment (Workings): Workings / Exploration = Workings consist of two bulldozer cuts, prospect pits, and a 40-foot shaft (now caved) (C.C. Hawley and Associates, Inc., 1978).

Comment (Deposit): Model Name = Fringe zone of Pb, Zn, and Ag sulfide mineralization to tin veins (generally related to the tin vein model of Cox and Singer, 1986; model 15b).

Comment (Commodity): Ore Material = Ytterbium

Comment (Geology): Geologic Description = The Mespelt prospect consists of two bulldozer cuts, several prospect pits, and a 40 foot shaft (now caved) constructed to evaluate a 7-foot-wide, 1000-foot-long quartz-carbonate vein that cuts the Tertiary-age Tonzona granitic pluton (Tmt), part of the McKinley sequence mapped by Reed and Nelson (1980). The vein, comprised of argentiferous galena, low-grade uranium, and tin mineralization, occurs beneath a gossan cap. High grade grab samples collected in 1959 contained 0.18 to 32.91 oz/ton Ag; trace Au, up to 46.4% Pb, 0.037 to 0.14% eU, up to 2.52% Sb, up to 0.06% Sn, and 0.01 to 0.04% W. A chip sample collected in 1956 assayed 56.3% WO3 (Maloney and Thomas,1966, Table 3; Reed and others, 1978). Greisen assemblages of quartz-tourmaline-muscovite are developed adjacent to the vein. Tin in excess of 1,500 ppm in the nonmagnetic heavy-mineral concentrates from stream silt samples collected from the Camp Creek drainage to the west of this prospect is reported by Curtin, Karlson, Tripp, and Day (1978).? the geologic setting of the Mespelt silver-lead-tin-tungsten vein is described, as follows, by C.C. Hawley and Associates, Inc., (1978) and Reed and Nelson (1980). Blocky slate, argillite, thin-bedded siliceous limestone and chert define a belt of lower Paleozoic sedimentary and metavolcanic rocks (possibly Keevy Peak, Totalanika series, or equivalents) bordered by the Tonzona granitic pluton. The granite has three phases: a coarse-grained, locally porphyritic biotite granite; a medium-grained biotite granite; and a late fine-grained, leucocratic, locally aplitic, muscovite - tourmaline granite in which ovoid clusters of small black tourmaline crystals give the rock a 'dalmatian' appearance. Muscovite may exceed biotite and accessory minerals include tourmaline with lesser amounts of topaz, fluorite, garnet, zircon, and apatite. Late-stage greissen veinlets, like those at the Mespelt propect, contain muscovite, topaz, tourmaline, locally abundant beryl, and occasionally, cassiterite. Lead, silver and tin mineralization occurs in Paleozoic metasediments and metavolcanic rocks along the north and northeast contact of the pluton. The Tonzona pluton has metamorphosed the country rocks to skarn assemblages along the contact and has formed skarn hosted polymetallic mineralization such as at the Jiles-Knudson (TL 004), Boulder Creek (TL073) and the nearby Hogback prospect (TL006). ? In much of the literature, the Jiles-Knudson, Mespelt, Hogback and Boulder Creek are included as the Purkeypile group of lode claims.

Comment (Geology): Age = Chron age is for McKinley Sequence.

Comment (Deposit): Other Comments = High grade samples were taken by the U.S. Bureau of Mines in 1959 and by the Alaska Division of Geological and Geophysical Surveys (C.C. Hawley and Associates, Inc., 1978). In much of the literature, the Jiles-Knudson, Mespelt, Hogback and Boulder Creek are included as the Purkeypile group of lode claims.? High grade grab samples collected in 1959 contained 0.18 to 32.91 oz/ton Ag; trace Au, up to 46.4% Pb, 0.037 to 0.14% eU, up to 2.52% Sb, up to 0.06% Sn, and 0.01 to 0.04% W. A chip sample collected in 1956 assayed 56.3% WO3 (Maloney and Thomas,1966, Table 3; Reed and others, 1978). Greisen assemblages of quartz-tourmaline-muscovite are developed adjacent to the vein. Tin in excess of 1,500 ppm in the nonmagnetic heavy-mineral concentrates from stream silt samples collected from the Camp Creek drainage to the west of this prospect is reported by Curtin, Karlson, Tripp, and Day (1978).

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References

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

Reference (Deposit): Clark, A.L., and Cobb, E.H., 1972, Metallic mineral resources map of the Talkeetna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-369, 1 sheet, scale 1:250,000.

Reference (Deposit): Capps, S.R., 1927, The Toklat-Tonzona River region: U.S. Geological Survey Bulletin 792-C, p. 73-110.

Reference (Deposit): Reed, B.L., and Nelson, S.W., 1980, Geologic map of the Talkeetna quadrangle: U.S. Geological Survey Miscellaneous Investigations Map I-1174, scale 1:250,000.

Reference (Deposit): Cobb, E.H., and Reed, B.L., 1980, Summaries of data and lists of reference to metallic and selected nonmetallic mineral deposits in the Talkeetna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-884, 106 p.

Reference (Deposit): C.C. Hawley and Associates, Inc., 1978, Mineral appraisal of lands adjacent to Mt. McKinley National Park, Alaska: U.S. Bureau of Mines Open-File Report 24-78, 275 p., 7 plates.

Reference (Deposit): Reed, B.L., Nelson, S.W., Curtin, G.C., and Singer, D.A., 1978, Mineral resources map of the Talkeetna Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-D, 1 sheet, scale 1:250,000.

Reference (Deposit): Curtin, G.C., Karlson, R.C., Tripp, R.B., and Day, G.W., 1978, Geochemical and generalized geologic map showing the distribution of tin, tungsten, and beryllium, Talkeetna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-F, 2 sheets, scale 1:250,000.

Reference (Deposit): Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

Reference (Deposit): Maloney, R.P., and Thomas, B.I., 1966, Investigation of the Purkeypile prospects, Kuskokwim River basin, Alaska: U.S. Bureau of Mines Open-File Report 5-66, 12 p.

Reference (Deposit): Reed, B.L., and Lanphere, M.A., 1972, Generalized geologic map of the Alaska-Aleutian range batholith showing potassium-argon ages of the plutonic rocks: U.S. Geological Survey Miscellaneous Field Studies Map MF-372, 2 sheets, scale 1:1,000,000.

Reference (Deposit): Capps, S.R., 1925, An early Tertiary placer deposit in the Yentna district: U.S. Geological Survey Bulletin 773, p. 53-61.

Reference (Deposit): Conwell, C.N., 1977, Boulder Creek tin lode deposits: Alaska Division of Geological and Geophysical Surveys Geologic Report 55, p. 35 -38.

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