Beaver

Prospect, Inactive

Commodities and mineralogy

Main commodities Zn
Other commodities Pb
Ore minerals cerussite; galena; smithsonite
Gangue minerals dolomite; ferrigenous gossan; secondary carbonate

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale B-3
Latitude 63.445
Longitude -154.118
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Beaver prospect is located on a south-facing slope at 1,950 feet (595 m) in elevation, upslope from the West Fork of Beaver Creek in Section 6, T. 24 S., R. 25 E., of the Kateel River Meridian. Location is known within 100 feet (30 m).

Geologic setting

Geologic description

At the Beaver prospect, mineralized rubble covers a 400 feet by 100 feet (122 m by 30 m) area in a sheet of gray dolomite of the Paradise Fork Formation of Dutro and Patton (1982). Smithsonite-rich, cerrusite-galena zones occur in well developed solution breccias, especially in recrystallized white, vuggy dolomite. Host unit trends N 45 E and dips 45 degrees South. Beaver is considered the best of a series of Mississippi Valley Type deposits exposed on the north limb of the Beaver Creek syncline. Other related deposits include Big Gate (MD050), Hillside (MD049), and Bermuda (MD045) showings. Host rock is Ordovician-Silurian, based on fossils in host unit (Blodgett, 1982); however, the age of the mineralization is unknown.
Grab samples from cerussite-rich gossan contain up to 32.7 percent zinc and 34.5 percent lead. A continuous trench sample that was composed of about 80 percent gossan contained 19.25 percent zinc and 0.90 percent lead over a 40 feet (12 m) interval (Schmidt, 1997).
Geologic map unit (-154.120329951256, 63.4444093938614)
Mineral deposit model Southeast Missouri Pb-Zn (Cox and Singer, 1986; model 32a) or Mississippi Valley type (Cox and Singer, 1986; model 32b).
Mineral deposit model number 32a or 32b
Age of mineralization Host rock is Ordovician-Silurian, based on fossils in host unit (Blodgett, 1982); however, the age of the mineralization is unknown.
Alteration of deposit White vuggy dolomite; galena to oxidized cerrusite.

Production and reserves

Workings or exploration The Beaver prospect was discovered by WGM Inc. and Patino Ltd. during exploration for base metals on lands in the 'Reef Ridge district.' Sporadic surface investigations were continued by Pasminco Ltd. until about 1989. Grab samples from cerussite-rich gossan contain up to 32.7 percent zinc and 34.5 percent lead. A continuous trench sample that was composed of about 80 percent gossan contained 19.25 percent zinc and 0.90 percent lead over a 40 feet (12 m) channel interval (Schmidt, 1997).
Indication of production None
Reserve estimates None.

Additional comments

See Bermuda (MD045), Hillside (MD049), and Big Gate (MD050) Mississippi Valley Type occurrences in Medfra B-3 quadrangle.

References

References

Anderson, G.M., and Macqueen, R.W., 1988, Mississippi Valley Type lead-zinc deposits, in Roberts, R.G., and Sheahan, P.A., eds., Ore deposit models: Geoscience Canada Reprint Series 3, Ottawa, Canada, p. 79-90.
Blodgett, R.B., 1982, Stratigraphy of Reef Ridge project area; WGM Inc., Anchorage, Alaska, Reef Ridge Project area, Block 10, Doyon region: WGM Inc., 34 pages.
Schmidt, J.M., 1997, Shale-hosted Zn-Pb-Ag and barite deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska, 1997: Economic Geology Monograph 9, p. 35-65.
Reporters Bundtzen, T.K. (Pacific Rim Geological Consulting)
Last report date 6/2/1998