Glacier Creek

Site Name

Primary: Glacier Creek
Secondary: Main Zone
Secondary: Palmer

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Commodity

Primary: Silver
Primary: Gold
Primary: Barium-Barite
Primary: Copper
Primary: Lead
Primary: Zinc

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Location

State: Alaska
District: Juneau (Skagway subdistrict)

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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: Massive sulfide, kuroko

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Text: Quartz-sericite-pyrite (phyllic) alteration and chloritic alteration developed within mafic metavolcanics.

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Barite
Ore: Sphalerite
Ore: Pyrite
Ore: Magnetite
Ore: Gold
Ore: Galena
Ore: Chalcopyrite
Gangue: Chlorite
Gangue: Quartz
Gangue: Sericite

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Comments

Comment (Reserve-Resource): Reserves = A resource of 750,000 tons of ore was estimated based on projecting the barite lenses down dip for 1/2 of their strike length (Still, 1984 [OF 118-84]).

Comment (Commodity): Ore Material = sulfosalts

Comment (Geology): Geologic Description = According to MacKevett and others (1974), the prospect is a barite-rich lode that occurs within a large altered, fault zone that cuts greenschist and subordinate quartzite. The fault zone is up to several hundred feet wide and dips steeply to the north. Near its easternmost exposure, the fault zone strikes about N60W but at its western end it strikes about N85E. The main barite-rich lode outcrops discontinuously over a distance of about 1/2 mile and a vertical extent of more than 1,000 feet. The lode is variably sheared and consists mainly of barite with sparsely disseminated sulfides and, locally narrow, sulfide-rich bands. The sulfides include pyrite, galena, sphalerite, and chalcopyrite. Secondary minerals include gypsum, azurite, chrysocolla, limonite, and rare anglesite, cerussite, and smithsonite. Minor amounts of sericite, chlorite and quartz gangue occur within the barite lode (MacKevett and others, 1974). The deposit consists of two lenses. The western lens averages 15 feet thick over a length of 250 feet and the eastern lens averages 70 feet thick over a length of 800 feet. Samples contain up to 45% barite, 7.8% zinc, 1.8% copper, 0.52% lead, 147.43 ppm silver, and 0.607 ppm gold. Based on an average of 15 composite samples, the mineralization is estimated to average 60% barite, 1.73% zinc, and 60 ppm silver (Still, 1984 [OF 118-84]); Still and others, 1991). The greenschist that hosts the mineralization and its quartz-sericite-pyrite alteration envelope is a mafic volcanic that locally contains well preserved pillows. More recent interpretations (since MacKevett and others, 1974) regard the prospect as a stratiform, volcanogenic, massive sulfide (Still, 1984 [OF 118-84]; Still and others, 1991; Newberry and others, 1997). The quartz-sericite-pyrite alteration surrounding the mineralization is itself surrounded by a foliated zone of chloritic alteration. The sericitization in the alteration envelope and the mineralization itself are less competent units that were probably preferentially sheared and faulted relative to the surrounding metavolcanics. Drilling by various different companies, including Anaconda in 1979 and Rubicon Minerals in 1998, intersected extensive alteration and thin or weakly mineralized intervals that did not approach ore-gradethickness. (T. Crafford, personal observation; Rubicon Minerals, 1998). Rubicon Minerals (1998) interprets the Main Zone to be part of a nearly 5-mile-long, northwesterly striking mineral trend that extends from the Red Creek prospect (SK063) at the southeast end through this prospect to the unnamed occurrences (SK070) in the steep slopes immediately south of the Jarvis Glacier. They believe this trend to be at or near the apex of a shallowly plunging, northwest-trending antiform that is subparallel to another, similar trend that extends through the Nunatak (SK058), Cap (SK060), and Mount Henry Clay (SK068) prospects. The Main Zone/Palmer and other similar prospects in the Mt. Henry Clay area are probably correlative with the Windy Craggy deposit in Canada and the Greens Creek deposit on Admiralty Island and are therefore Late Triassic (Still, 1984 [OF 118-84]; Newberry and others, 1997).

Comment (Geology): Age = Probably Late Triassic based on inferred relations to the Greens Creek Mine on Admiralty Island and the Windy Craggy deposit (Still, 1984 [OF 118-84]; Newberry and others, 1991).

Comment (Deposit): Model Name = Probably a Besshi- or Kuroko-type volcanogenic massive sulfide (Cox and Singer, 1986; models 28a or 24b).

Comment (Reference): Primary Reference = Still, 1984 (OF 118-84)

Comment (Workings): Workings / Exploration = The deposit was discovered in 1969 and 1971 by Merril Palmer and associates (MacKevett and others, 1974). A 3,000-pound bulk sample collected by ALYU Mining assayed 76.4% barite, 3.6% zinc, 0.98% copper, 0.12% lead, and 92 ppm silver (Still, 1984 [OF 118-84]). This prospect has been explored by numerous companies, including the Anaconda Minerals Company, Kennecott Alaska Exploration, Newmont Gold Company, Granges Inc., Cominco Alaska, Inc., Teck Corporation, and Rubicon Minerals-Atna Resources Ltd. Exploration expenditures in the area, including Mt. Henry Clay and other nearby volcanogenic massive sulfide occurrences through 1998 are estimated to be approximately US$2.2 million.

Comment (Exploration): Status = Active

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References

Reference (Deposit): MacKevett, E.M., Jr., Robertson, E.C., and Winkler, G.R., 1974, Geology of the Skagway B-3 and B-4 quadrangles, southern Alaska: U.S. Geological Survey Professional Paper 832, 33 p.

Reference (Deposit): Newberry, R.J., Crafford, T.C., Newkirk, S.R., Young, L.E., Nelson, S.W., and Duke, N.A., 1997, Volcanogenic massive sulfide deposits of Alaska, in Goldfarb, R.J. and Miller, L. D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 120-150.

Reference (Deposit): Still, J.C., Hoekzema, R.B., Bundtzen, T.K., Gilbert, W.G., Wier, K.R., Burns, L.E., and Fechner, S.A., 1991, Economic geology of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-4, 156 p., 5 sheets, scale 1:63,360.

Reference (Deposit): MacKevett, E.M., Jr., 1971, Analyses of samples and preliminary geologic summary of barite-silver-base metal deposits near Glacier Creek, Skagway B-4 quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 71-195, 8 p.

Reference (Deposit): Rubicon Minerals, 1998, Palmer VMS Project, southeast Alaska, Executive Summary: unpublished report by Rubicon Minerals Corporation, Vancouver, British Columbia, 25 p.

Reference (Deposit): Gilbert, W.G., and Redman, E.C., 1989, Lode deposits, prospects, and occurrences of the Porcupine mining area, southeast Alaska: U.S. Bureau of Mines Open-File Report 17-89, 1 sheet, scale 1:39,600.

Reference (Deposit): Forbes, R.B., Gilbert, W.G., and Redman, E., 1989, Geologic setting and petrology of the metavolcanic rocks in the northwestern part of the Skagway B-4 Quadrangle, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Public-Data File 89-14, 46 p.

Reference (Deposit): Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

Reference (Deposit): Still, J.C., 1984, Stratiform massive sulfide deposits in the Mt. Henry Clay area, southeast Alaska: U.S. Bureau of Mines Open-File Report 118-84, 65 p.

Reference (Deposit): Hawley, C.C., 1976, Stratabound volcanogenic deposits in Alaska: Alaska Geological Society Symposium, 4th, Anchorage, Alaska, April 1975, Proceedings, p. T1-T23.

Reference (Deposit): Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mt. Fairweather and Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-316, 123 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Skagway quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-424, 1 sheet, scale 1:250,000.

Reference (Deposit): Redman, E.C., 1983, Reconnaissance geology of the Glacier Creek area, Skagway B-4 quadrangle, Alaska, in Appendix B of Still, J.C., 1984, Stratiform massive sulfide deposits in the Mt. Henry Clay area, southeast Alaska: U.S. Bureau of Mines Open-File Report 118-84, 65 p.

Reference (Deposit): Berg, H.C., 1984, Regional geologic summary, metallogenesis, and mineral resources of southeastern Alaska: U.S. Geological Survey Open-file Report 84-572, 298 p., 1 plate, scale approx. 1:600,000.

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