Lucrata

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

Geologic information

Identification information

Deposit ID 10000693
MRDS ID A011322
Record type Site
Current site name Lucrata
Alternate or previous names Lucrative Group

Geographic coordinates

Geographic coordinates: -149.53172, 63.26459 (WGS84)
Relative position The Lucrata prospect is at an elevation of about 2,700 feet on the west bank of Costello Creek, about 0.3 mile south of the Dunkle mine camp. It is in sec. 18, T. 19 S., R. 10 W., of the Fairbanks Meridian. Accuracy of location is to within 500 feet. This is locality 2 of Cobb (1978: OFR 78-1062).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Chalcopyrite Ore
Quartz Gangue

Alteration

  • (Local) Quartz-sericite-pyrite alteration.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro
    Stratigraphic age (youngest) Pliocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro

Nearby scientific data

(1) -149.53172, 63.26459

Comments on the geologic information

  • Geologic Description = The general area of this prospect is characterized by thick Quaternary glacial deposits and Upper Tertiary sedimentary strata that mostly cover Upper Jurassic to Upper Triassic(?) crystal tuff, argillite, chert, graywacke, and limestone (Wilson and others, 1998). Upper Cretaceous quartz diorite dikes cut the mesozoic bedded rocks, mainly along the nearby Chulitna fault. At the Lucrata prospect, arsenopyrite-chalcopyrite pods up to 4 feet thick and 5 feet long area in a quartz stockwork in gabbro and basalt along the Chulitna fault zone. Assay values as high as 1.26 ounces of gold per ton and 3.8 ounces of silver per ton are reported by Hawley and Clark (1974); average grades of 0.49 ounce of gold per ton and 1.03 ounces of silver per ton are reported by Bundtzen (1983).
  • Age = Late Cretaceous or younger, assuming that the deposit is related to the intrusion of the quartz diorite.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Active

Mining district

District name Valdez Creek

Comments on the workings information

  • Workings / Exploration = There has been both surface and underground exploration; a 15 ft tunnel was driven in 1920. Assay values as high as 1.26 ounces of gold per ton and 3.8 ounces of silver per ton are reported by Hawley and Clark (1974); average grades of 0.49 ounce of gold per ton and 1.03 ounces of silver per ton are reported by Bundtzen (1983).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A011322
USGS Alaska Resource Data File ARDF HE029

Bibliographic references

  • Deposit

    Townsend, H.H., 1925, Assay returns: Alaska Territorial Dept. of Mines Itinerary Report 195-48, 4 p.

  • Deposit

    Ross, C.P., 1933, The Valdez Creek mining district, Alaska: U.S. Geological Survey Bulletin 849, p. 289-467.

  • Deposit

    Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

  • Deposit

    Hawley, C.C., and Clark, A.L., 1968, Occurence of gold and other metals in the upper Chulitna district, Alaska: U.S. Geological Survey Circular 564, 21 p.

  • Deposit

    Hawley, C.C., and Clark, A.L., 1974, Geology and mineral deposits of the upper Chulitna district, Alaska: U.S. Geological Survey Professional Paper 758-B, p. 1-47, 2 sheets, scale 1:12,000 and 1:48,000.

  • Deposit

    Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Healy quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-1062, 113 p.

  • Deposit

    Bundtzen, T.K., 1983, Mineral resource modeling, Kantishna and Dunkle mine study areas: Alaska Division of Geological "&" Geophysical Surveys Report of Investigations 83-12, 51 p.

  • Deposit

    Balen, M.D., 1990, Geochemical sampling results from the Bureau of Mines Investigations in the Valdez Creek mining district, Alaska: U.S. Bureau of Mines Open-File Report 34-90, 218 p., 2 plates, scale 1:250,000.

  • Deposit

    Wilson, F.H., Dover, J.H., Bradley, D.C., Weber, F.R., Bundtzen, T.K., and Haeussler, P.J., 1998, Geologic map of central (interior) Alaska: U.S. Geological Survey Open-File Report 98-133, 17 p., 2 sheetsm, scale 1:500,000.

  • Deposit

    Capps, S.R., 1919, Mineral resources of the upper Chulitna region: U.S. Geological Survey Bulletin 692-D, p. 207-232.

Comments on the references

  • Primary Reference = Ross, 1933

General comments

Subject category Comment text
Deposit Model Name = Polymetallic vein (Cox and Singer, 1986; model 22c)
Deposit Other Comments = the Lucrata prospect has also been referred to as the Dunkle mine. This should be dropped as it invites comparison to the Dunkle coal mine, a separate deposit.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-APR-00 N. Van Wyck Stevens Exploration Management Corporation