Grenadier

The Grenadier is a copper 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: Grenadier

Commodity

Primary: Copper

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

Alteration Type: L
Alteration Text: Probably local silicification, carbonatization, pyritization, and introduction of hydrothermal hematite.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Chalcopyrite
Gangue: Quartz

Comments

Comment (Geology): Age = Late Triassic or younger.

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

Comment (Reference): Primary Reference = Brooks, 1902; Maas and others, 1995

Comment (Geology): Geologic Description = Southern Gravina Island is underlain by an assemblage of undivided Silurian or Ordovician metamorphosed bedded and intrusive rocks; a stock and associated dikes of Silurian trondhjemite that cuts the metamorphic assemblage; and a sequence of Upper Triassic carbonate, clastic, rhyolitic, and basaltic strata that unconformably overlies the older rocks (Berg, 1973, 1982; Berg and others, 1988). The rocks are complexly folded and are cut by high-angle faults and by low-angle thrust faults. In many places, the Triassic rhyolite and the rocks beneath it are permeated by microscopic particles of hydrothermal hematite, giving them a pink, purple, or red hue (Berg, 1973, p. 14). Brooks (1902, p. 73) describes the Grenadier prospect as a mineralized shear or breccia zone at the contact of pegmatite with schist and greenstone. . Maas and others' (1995, p. 227) description of the mineral deposits in the area north of Dall Bay probably applies in general to the Grenadier deposit. They report that chalcopyrite is associated with sheared, silicified zones, chiefly in trondhjemite. Small barite veins are also found in the area. About 0.6 mile north of Dall Bay, chalcopyrite occurs as clasts or pods in a siderite-hematite matrix in altered trondhjemite. The Grenadier prospect is near the intersection of high-angle, NE- and NW-striking faults that juxtapose trondhjemite and metavolcanic rocks (Maas and others, 1995, fig. 58). The characteristics and setting of the deposits suggest that they mainly are polymetallic veins of Late Triassic or younger age.

References

Reference (Deposit): Berg, H.C., 1973, Geology of Gravina Island Alaska: U.S. Geological Survey Bulletin 1373, 41 p.

Reference (Deposit): Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.

Reference (Deposit): Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 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.

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., 1982, The Alaska Mineral Resource Assessment Program; guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Circular 855, 24 p.

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