Halobia

The Halobia is a lead, zinc, and silver mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Halobia

Commodity

Primary: Lead
Primary: Zinc
Primary: Silver
Secondary: Arsenic
Secondary: Barium-Barite
Secondary: Copper

Location

State: Alaska
District: Kupreanof

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Massive sulfide, Sierran kuroko
Model Name: Massive sulfide, kuroko

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: None.

Rocks

Name: Phyllite
Role: Host
Age Type: Host Rock
Age Young: Late Triassic

Analytical Data

Not available

Materials

Ore: Galena
Ore: Pyrite
Ore: Sphalerite

Comments

Comment (Geology): Age = Unambiguously Late Triassic as defined by the occurrence of the fossils of Halobia at the site.

Comment (Geology): Geologic Description = Thin lenses of massive sulfides occur in siliceous phyllite that is intercalated with fossiliferous , Upper Triassic, black carbonaceous phyllite; locally garnet-bearing limestone; siltstone; and silvery dark gray muscovite- and quartz-rich phyllite (Berg and Grybeck, 1980; Berg, 1981). The carbonaceous phyllite contains abundant pyrite. The massive sulfide lenses are in several zones 10-12 feet wide and 80-100 feet long. Individual lenses within these zones are up to 1 foot wide and 3 feet long; they contain abundant pyrite and up to 5% galena and sphalerite. Analyses of grab samples show up to 100 ppm Cu, 100 ppm Ag, and 1000 ppm As. Several examples of the fossil Halobia collected in rocks interbedded with the sulfide lenses at the deposit unambiguously date the deposit as Late Triassic. Unpublished work by industry indicated more examples of similar deposits have been found in the claims staked northwest of this prospect (see 'Workings/Description' field ). The deposit is part of the Triassic Duncan Canal-Zarembo Canal belt of dismembered, volcanogenic massive-sulfide deposits described by Berg and Grybeck (1980) and Berg (1981).? Brew (1997 [OF 97-156-J]) indicates that the deposit is in a sliver of Triassic Hyd Group rocks that consist mainly of phyllite and slate with minor conglomerate, limestone and sandstone. However, the Hyd Group rocks are surrounded by a large, poorly-exposed area of undated phyllite, slate, and minor conglomerate, limestone, and quartzite to which Brew assigns a Mesozoic age. This unit is largely covered by vegetation and probably includes substantial additional Triassic Hyd Group rocks that may contain similar deposits. Recent mapping (Sue Karl, oral communication, 1998) indicates that Brew's Mesozoic unit also may include argillite and volcanic graywacke of the Mississippian and Permian Cannery Formation. Also see PE024 which is probably of similar origin if not a continuation of this site.

Comment (Reference): Primary Reference = Berg and Grybeck, 1980; this description

Comment (Workings): Workings / Exploration = Originally found by the U. S. Geological Survey in 1979 (Berg and Grybeck, 1980). Nine lode claims staked on the deposit in 1979; by 1995, a considerable block of ground several square miles in area was staked on and northwest of the original discovery (Department of Natural Resources unpublished Kardex mining claim information system). Informal discussions with industry geologists who worked in the area indicate that they have identified several to numerous additional occurrences of similar deposits on these claims. (The latitude and longitude of this site are the location of the original discovery.) An aerial examination of the area in 1996 indicated no obvious signs of surface exploration in the vicinity. In 1998, there was renewed interest in the area encouraged by the geophysical surveys the State of Alaska flew over the area in 1997.

Comment (Production): Production Notes = None

Comment (Exploration): Status = Active

Comment (Deposit): Model Name = Kuroko massive-sulfide deposit model (Cox and Singer, 1986, model 28a); alternately a Sierran Kuroko deposit (Bliss, 1992; 28a1)

Comment (Reserve-Resource): Reserves = None

References

Reference (Deposit): Berg, H. C., and Grybeck, Donald, 1980, Upper Triassic volcanogenic Zn-Pb-Ag (-Cu-Au) mineral deposits near Petersburg, Alaska: U.S. Geological Survey Open-File Report 80-527, 11 p., 1 oversize sheet.

Reference (Deposit): Berg, H.C., 1981, Upper Triassic volcanogenic massive sulfide metallogenic province identified in southeastern Alaska, in Albert, N.R.D., and Hudson, T.L., eds., The United States Geological Survey in Alaska: accomplishments during 1979: U.S. Geological Survey Circular 823-B, p. B104-B108.

Reference (Deposit): Brew, D.A., 1997, Reconnaissance geologic map of the Petersburg C-4 quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 97-156-J, 21 p., 1 sheet, scale 1:63,360.

Reference (Deposit): Grybeck, D.J., Berg, H.C., and Karl, S.M., 1984, Map and description of the mineral deposits in the Petersburg and eastern Port Alexander quadrangles: U.S. Geological Survey Open-File Report 84-837, 86 p., 1 sheet, scale 1:250,000.

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