Eneveloe (Bonanza

Site Name

Primary: Eneveloe (Bonanza
Secondary: Jupiter
Secondary: Woodchuck
Secondary: Venus
Secondary: Golden Eagle
Secondary: First Chance
Secondary: Last Chance
Secondary: Envelope)

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Commodity

Primary: Gold
Secondary: Silver
Secondary: Copper
Secondary: Antimony
Secondary: Lead
Secondary: Zinc

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Location

State: Alaska
District: Chandalar

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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: Low-sulfide Au-quartz vein

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Orebody

Not available

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Structure

Not available

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Alterations

Not available

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Rocks

Role: Host
Age Type: Host Rock
Age Young: Devonian

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Analytical Data

Not available

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Materials

Ore: Scorodite
Ore: Gold
Ore: Galena
Gangue: Quartz

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Comments

Comment (Geology): Age = Host rock is Devonian.

Comment (Exploration): Status = Inactive

Comment (Geology): Age = Middle Cretaceous based on arguments by Dillon (1982) that the age of emplacement of the gold-bearing quartz veins of the Koyukuk and Chandalar districts was between the Neocomian metamorphism of the Devonian host rocks and their erosional unroofing and cooling in Albian time.

Comment (Geology): Geologic Description = The Eneveloe lode consists of discontinuous quartz veins 4 to 6 feet wide, at least one of which carries free gold. According to Maddren (1913) a sample from a surface outcrop on the Last Chance claim assayed $198 (approximately 9.6 oz of gold). Prospect pits on the Jupiter claim, located along the Summit fault west of the Summit mine, exposed quartz containing minor arsenopyrite and scorodite. In the area of the Eneveloe and Bonanza claims, minor quartz veins crop out and prospect pits expose small and discontinuous quartz veins containing minor galena and scorodite. The veins are traceable for 1,500 feet and generally dip steeply south.? the Eneveloe lode is one of several gold-bearing quartz veins in the Chandalar district, an area approximately 1 mile wide and 2 1/2 miles long lying between the heads of Big, Tobin, Squaw and Little Squaw creeks. The principal deposits in this area are localized along three steeply dipping, northwest-trending normal faults in Devonian quartz-muscovite schist, phyllite and quartzite, intruded by Devonian mafic sills and dikes (Chipp, 1970). The mafic intrusions have been metamorphosed to greenstone or greenschist. From north to south these normal faults are the Little Squaw, Summit, and Mikado.? the Eneveloe property is along the Summit fault a short distance west of the Summit mine. Most of the quartz veins in the district are discontinuous along the structures, generally pinching out within a few hundred feet or less. Widths may vary from a few inches to several feet but are generally less than 10 feet. The quartz veins exhibit evidence of shearing, which indicates that the veins were emplaced before or during fault movement. Sulfide content of the veins is typically less than 5 percent, with the primary sulfides being, in relative order of abundance, arsenopyrite, galena, sphalerite, and pyrite. Much of the gold occurs as native gold. Weathering near the surface has oxidized and leached the sulfides to produce scorodite and limonite. The genesis of these gold deposits is still in question, although various authors have hypothesized genetic links to a variety of felsic and mafic igneous rocks from which the gold was remobilized during metamorphism (Mertie, 1925; Boadway, 1933; Chipp, 1970; Dillon, 1982).

Comment (Deposit): Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Comment (Reference): Primary Reference = Chipp, 1970

Comment (Workings): Workings / Exploration = Surface and underground workings include an adit 165 feet in length driven before 1913 between the First Chance and Last Chance claims that extend along the vein to a depth of 40 feet (Maddren, 1913). Another adit was opened on the Woodchuck claim, but there is no description of its extent. The property has also been explored along 1,000 feet of its length by open cuts and other shallow workings.

Comment (Deposit): Other Comments = See also: Summit (CH041), Star (CH042), Mikado (CH045), Little Squaw (CH040). The Eneveloe claim, along with the Bonanza and Golden Eagle, are shown on U.S. Mineral Survey 1995. The Jupiter and Woodchuck claims are shown on U.S. Mineral Survey 1629, and the Venus claims on U.S. Mineral Survey 1630.

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References

Reference (Deposit): Maddren, A.G., 1913, The Koyukuk-Chandalar region, Alaska: U.S. Geological Survey Bulletin 532, 119 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-457, 1 sheet, scale 1:250,000.

Reference (Deposit): Chipp, E.R., 1970, Geology and geochemistry of the Chandalar area, Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 42, 39 p., 1 sheet, scale 1:36,000.

Reference (Deposit): Boadway, E.A., 1933, Report on Mikado and Little Squaw veins, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-7, 37 p.

Reference (Deposit): Boadway, E.A., 1932, Report on Sulzer properties, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-6, 23 p., 4 sheets.

Reference (Deposit): Heiner, L.E., and Wolff, E.N., eds., 1968, Mineral resources of northern Alaska, Final report, submitted to the NORTH Commission: Mineral Industry Research Laboratory, University of Alaska, Report 16, 306 p.

Reference (Deposit): Stanford, J.V., 1931, Report on Little Squaw, Bonanza, and Mikado groups of claims, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-5, 10 p.

Reference (Deposit): Reed, I.M., 1930, Report on the Little Squaw area of the Chandalar mining district: Alaska Territorial Department of Mines Miscellaneous Report 31-4, 18 p.

Reference (Deposit): DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.

Reference (Deposit): Bundtzen, T.K., Eakins, G.R., Clough, J.G., Lueck, L.L., Green, C.B., Robinson, M.S., and Coleman, D.A., 1984, Alaska's Mineral Industry, 1983: Alaska Division of Geological and Geophysical Surveys Special Report 33, 56 p.

Reference (Deposit): Cobb, E.H., and Cruz, E.L., 1983, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in the Chandalar quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-278, 91 p.

Reference (Deposit): Anderson, Eskil, 1944, Petrographic descriptions of rocks collected during 1944 field investigation in north-west Alaska, and lists of ore and rock samples and placer concentrates collected in northwestern and interior Alaska during 1945 field season: Alaska Territorial Department of Mines Miscellaneous Report 195-28, 76 p.

Reference (Deposit): Dillon, J.T., 1982, Source of lode and placer gold deposits of the Chandalar and upper Koyukuk Districts: Alaska Division of Geological and Geophysical Surveys Open-File Report 158, 25 p., 1 sheet, scale 1:250,000.

Reference (Deposit): Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Chandalar and Wiseman quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-340, 205 p.

Reference (Deposit): Reed, I.M., 1927, Report on some of the quartz prospects of the Chandalar district: Alaska Territorial Department of Mines Miscellaneous Report 31-2, 4 p.

Reference (Deposit): Mertie, J.B., Jr., 1925, Geology and gold placers of the Chandalar district, in Brooks, A.H., and others, Mineral resources of Alaska, report on progress of investigations in 1923: U.S. Geological Survey Bulletin 773, p. 215-263.

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