Falck

Prospect in Alaska, United States with commodities Copper, Zinc, Silver

Geologic information

Identification information

Deposit ID 10000357
MRDS ID A010422
Record type Site
Current site name Falck
Related records 10112625

Geographic coordinates

Geographic coordinates: -146.57143, 60.8657 (WGS84)
Relative position The Falck prospect is at an elevaation of about 2400 ft., about 0.5 mile east of Copper Mountain. It is in S1/2 sec. 36, T. 11 S., R. 8 W., of the Copper River Meridian. The location is accurate to within 1000 ft. This prospect is shown as #12 in Cobb (1972: MF-392) and as C-78 in Jansons and others (1984).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Zinc Primary
Silver Secondary

Comments on the commodity information

  • Ore Material = Copper (native)

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Copper Ore
Calcite Gangue
Quartz Gangue

Mineral occurrence model information

Model code 90
USGS model code 24a
Deposit model name Massive sulfide, Cyprus
Mark3 model number 11

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock
    Rock unit name Orca Group;Orca Group
    Rock description Orca Group;Orca Group

Nearby scientific data

(1) -146.57143, 60.8657

Comments on the geologic information

  • Geologic Description = The country rocks at this prospect are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of sulfide minerals and native copper in veinlets and as disseminations in a northwest-striking, steeply-dipping shear zone in the volcanic and sedimentary rocks (Capps and Johnson, 1915). The sulfides are chalcopyrite, pyrite, pyrrhotite, and sphalerite.? Analyses of chip samples contained 0.11% to 7.5% Cu, 240 ppm to 0.68% Zn, and 0.7 ppm to 18.3 ppm Ag (Jansons and others, 1984).
  • Age = Probably Tertiary based on the age of the host rocks.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Copper River

Comments on the reserve resource information

  • Reserves = Inferred reserves of 200 tons @ 2.03% Cu, 0.23% Zn, 13 ppm Ag (Jansons and others, 1984).

Comments on the workings information

  • Workings / Exploration = Capps and Johnson (1915) report a 25 ft. adit and a 15 ft. adit, along with minor surface cuts. In the 1980s only the 25 ft. adit was still accessible (Jansons and others, 1984). Analyses of chip samples contained 0.11% to 7.5% Cu, 240 ppm to 0.68% Zn, and 0.7 ppm to 18.3 ppm Ag (Jansons and others, 1984).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010422
USGS Alaska Resource Data File ARDF CV015

Bibliographic references

  • Deposit

    Capps, S.R., and Johnson, B.L., 1915, The Ellamar district, Alaska: U.S. Geological Survey Bulletin 605, 125 p.

  • Deposit

    Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, Southcentral Alaska: U.S. Bureau of Mines Open-File Report 5-84, 218 p., 2 sheets, scale 1:250,000.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1992, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska: Economic Geology, v. 87, p. 1722-1746.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska-A reply: Economic Geology, v. 88, p. 1285-1288.

  • Deposit

    Sainsbury, C.L., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska, A discussion: Economic Geology, v. 88, p. 1284-1285.

  • Deposit

    Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Cordova quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-392, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Jansons and others, 1984

General comments

Subject category Comment text
Deposit Model Name = Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Deposit Other Comments = Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area.? Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-JUN-2000 S.W. Nelson U.S. Geological Survey