Cinnabar Creek placer

Prospect in Alaska, United States with commodities Mercury, Antimony

Geologic information

Identification information

Deposit ID 10002510
MRDS ID A013451
Record type Site
Current site name Cinnabar Creek placer

Geographic coordinates

Geographic coordinates: -158.86668, 60.79434 (WGS84)
Relative position This placer cinnabar prospect is located in a northeast headwater tributary of Cinnabar Creek locally called Cinnabar Run and Cinnabar Gulch. The placer is about 1 mile long from its origin as a residual deposit over the Cinnabar Creek lode deposit (TA001) at the head of Cinnabar Gulch. The map site is the approximate midpoint of the placer on Cinnabar Run, in the SW1/4 of section 12, T 8 N, R 55 W, of the Seward Meridian. It is 0.5 mile north-northeast of the north end ot the Cinnabar Creek airstrip. This prospect is accurately located. It is locality 9 of Cobb (1972 [MF 384]; 1976 [OF 76-606]).
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Geographic areas

Country State
United States Alaska


Commodity Importance
Mercury Primary
Antimony Secondary

Materials information

Materials Type of material
Cinnabar Ore
Stibnite Ore
Quartz Gangue

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Gravel
    Stratigraphic age (youngest) Holocene

Nearby scientific data

(1) -158.86668, 60.79434

Comments on the geologic information

  • Geologic Description = Russell Schaeffer and Harvey Winchell found this placer cinnabar deposit in 1941, the year they staked placer claims on Cinnabar Creek, Cinnabar Run, and Cinnabar Gulch (Rutledge, 1950, p. 3). The deposit was subsequently explored by dozer cuts in its upper part and by many test pits. The alluvium in the drainage is only about 100 to 150 feet wide, and in places the paystreak is only about 25 feet wide. The paystreak is at least 3,100 feet long. It is covered by up to 18 feet of colluvium/alluvium in Cinnabar Gulch and by about 7 feet of alluvial gravel along Cinnabar Run and Cinnabar Creek. Although Cady and others (1955) reported that the paystreak was only about 2 to 6 inches thick, test pits indicate that the minable section commonly is 5 feet thick and in the upstream part of the deposit, up to 14 feet thick (Rutledge, 1950, fig. 7). The placer contains many coarse nuggets to fist size of finely crystalline cinnabar, and many nuggets of cinnabar intergrown with quartz, stibnite, and breccia fragments of siltstone. The nuggets are angular in Cinnabar Gulch and well-rounded downstream along Cinnabar Run. Data from 14 test pits, mostly along Cinnabar Run, show that the paystreak is continuous, although locally narrow, and contains 0.21 to 0.84 percent Hg over mining sections varying from 5 to 14 feet thick (Rutledge, 1950, fig. 7). A few nuggets were obtained from a remnant bench placer deposit 40 feet above the Cinnabar Run flood plain.
  • Age = Quaternary.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Aniak

Comments on the production information

  • Production Notes = Production from this placer deposit has not been reported; it is not clear if mining has taken place (Sainsbury and MacKevett, 1965, p. 42).

Comments on the reserve resource information

  • Reserves = It is possible that much of this deposit is still in place. If the deposit is 4,000 feet long, 25 feet wide, 5 feet thick, and averages 0.4 pounds of Hg per cubic yard, then the contained resource is about 2,200 pouinds of mercury.

Comments on the workings information

  • Workings / Exploration = Many test pits and some dozer trenches, including one 390 feet long and up to 18 feet deep excavated by the U. S. Bureau of Mines, have explored this placer deposit.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013451
USGS Alaska Resource Data File ARDF TA002

Bibliographic references

  • Deposit

    Rutledge, F.A., 1950, Investigation of mercury deposits, Cinnabar Creek area, Georgetown and Akiak districts, Kuskokwim region, southwestern Alaska: U.S. Bureau of Mines Report of Investigations 4719, 9 p.

  • Deposit

    Cady, W.M., Wallace, R.E., Hoare, J.M., and Webber, E.J., 1955, The central Kuskokwim region, Alaska: U.S. Geological Survey Professional Paper 268, 132 p.

  • Deposit

    Sainsbury, C.L. and MacKevett, E.M., Jr., 1965, Quicksilver deposits of southwestern Alaska: U.S. Geological Survey Bulletin 1187, 89 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Taylor Mountains quadrangle: U.S. Geological Survey Miscellaneous Field Studies Map MF-384, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Dillingham, Sleetmute, and Taylor Mountain quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-606, 92 p.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Dillingham, Sleetmute, and Taylor Mountains quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-606, 92 p.

Comments on the references

  • Primary Reference = Rutledge, 1950

General comments

Subject category Comment text
Deposit Model Name = Alluvial placer cinnabar

Reporter information

Type Date Name Affiliation Comment
Reporter 30-DEC-2000 Travis L. Hudson Applied Geology