Nanjan

The Nanjan is a molybdenum 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: Nanjan

Commodity

Primary: Molybdenum

Location

State: Alaska
District: Ketchikan

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: Polymetallic veins

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Molybdenite
Gangue: Quartz

Comments

Comment (Deposit): Other Comments = the prospect is in Misty Fiords National Monument Wilderness.

Comment (Deposit): Model Name = Polymetallic vein? (Cox and Singer, 1986; model 22c)

Comment (Geology): Age = Late Cretaceous or younger

Comment (Reference): Primary Reference = Maas and others, 1995

Comment (Workings): Workings / Exploration = Molybdenite mineralization was discovered at the Nanjan property in about 1935, Workings in the 1930s included trenches, opencuts, test pits, and shafts, but little of the work was evident in 1992 (Maas and others, 1995). Samples collected by Maas and others (1995, p. 269) along the Nanjan vein revealed low precious- and base-metal values. The highest molybdenum analysis was 0.25% Mo in a selected sample, and 0.20% Mo across a 4-foot-wide section of the vein.

Comment (Geology): Geologic Description = The Nanjan prospect area is underlain by an assemblage of undivided Mesozoic or Paleozoic metamorphosed sedimentary, volcanic, and intrusive rocks; and by a stock and dikes of Cretaceous granodiorite and quartz diorite (Berg and others, 1988, p. 21, 22). The undivided assemblage was regionally metamorphosed to amphibolite grade in middle or Late Cretaceous Cretaceous time, and locally remetamorphosed to hornblende hornfels near the contacts of some of the granodiorite and quartz diorite plutons. The prospect is situated on a prominent high-angle fault of unknown displacement that strikes north-northwest, along the valley of the unnamed creek that adjoins the property (Maas and others, 1995, fig. 70). The Nanjan prospect consists of sparse nodules of pyrite and molybdenite in a quartz fissure vein that reportedly lies near the contact of hornblende granite and altered limestone (Maas and others, 1995, p. 268). The vein strikes between N40W and N20E and dips generally to the west. the vein is up to 8 feet thick, but probably averages less than 3 feet thick; it is exposed intermittently along strike for at least 1300 feet. Most of the molybdenite is associated with fault gouge that bounds the vein. The vein apparently is younger than most or all of the middle or Late Cretaceous regional metamorphism, but older than an episode of local(?) faulting. Molybdenite mineralization was discovered at the Nanjan property in about 1935, Workings in the 1930s included trenches, opencuts, test pits, and shafts, but little of the work was evident in 1992 (Maas and others, 1995). Samples collected by Maas and others (1995, p. 269) along the Nanjan vein revealed low precious- and base-metal values. The highest molybdenum analysis was 0.25% Mo in a selected sample, and 0.20% Mo across a 4-foot-wide section of the vein.

References

Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

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