Arsenic Creek

Prospect in Alaska, United States with commodities Mercury, Arsenic

Geologic information

Identification information

Deposit ID 10002460
MRDS ID A013390
Record type Site
Current site name Arsenic Creek
Related records 10234189

Geographic coordinates

Geographic coordinates: -160.13275, 59.99931 (WGS84)
Relative position Arsenic Creek is a small, south-headwater tributary of Rainy Creek (BH002). This lode prospect is on the south side of Arsenic Creek, at an elevation of about 1,700 feet and about 1,000 feet upstream of the confluence with Rainy Creek. This is locality 5 of Cobb (1972 [MF 455]) and of Hoare and Cobb (1977). It is in the Togiak National Wildlife Refuge and the Togiak Wilderness.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Mercury Primary
Arsenic Secondary

Materials information

Materials Type of material
Cinnabar Ore
Orpiment Ore
Realgar Ore
Quartz Gangue

Alteration

  • (Local) Silicification.

Host and associated rocks

  • Host or associated Host
    Stratigraphic age (youngest) Campanian
    Stratigraphic age (oldest) Barremian

Nearby scientific data

(1) -160.13275, 59.99931

Comments on the geologic information

  • Geologic Description = Lode mercury mineralization was identified on Arsenic Creek sometime between 1910 and 1920 (Rutledge, 1948). In 1947, the U. S. Bureau of Mines completed 1,500 feet of dozer trenching and 1,440 feet of hand trenching in the area of known lode mineralization (Rutledge, 1948). Three separate small but high-grade lode deposits were identified over a distance of 200 feet on the south side of the creek. These deposits are along or within 50 feet of the creek. The larger deposit (Deposit 1 of Rutledge, 1948, p. 5) is a sheared and fractured zone that is primarily developed in sandstone. The enclosing shears strike N 30 to 35 E, approximately parallel to bedding, but dip 70 northwest, opposite to bedding. Mineralization in the sheared zone includes realgar, cinnabar, and quartz in vein stockworks and seams along fractures and bedding. Eight samples collected over the 25-foot wide zone ranged in grade from 0.6 to 35.4 pounds of mercury per ton; a weighted average for these samples is 3.4 pounds of Hg per ton. Rutledge (1948, p. 5) concluded that the mineralized zone had a rhombohedral, pipe-like form and could not be traced along strike. Another lode deposit, 100 feet upstream, is similar in form but smaller. Five samples from this deposit ranged in grade from 1.6 to 44.6 pounds of Hg per ton; the higher grades were from thin sulfide-rich zones, including silicified shale, only a few inches thick. The third lode deposit, 200 feet east of the first, includes small lenses of white and gray quartz with enclosed cinnabar along a vertical N 30 E-striking fault zone. A composite sample of three, 3- to 6-inch-thick high grade lenses contained 45.8 pounds of Hg per ton. Arsenic, up to 18 percent or more, is present in all samples. In the larger deposits, realgar is the most abundant sulfide mineral. Orpiment is locally present. A realgar- and orpiment-rich sample contained 0.05 ppm Au (Frost, 1990, table 1, sample 7TF003). Although specific lode deposits could not be traced along strike, dozer trenches revealed thin mercury-bearing zones over about 700 feet of length; 0.5- to 1.6-foot-wide samples from these trenches contained 0.2 to 3.4 pounds of Hg per ton and 0.05 to 0.1 percent As. The bedrock in Arsenic Creek is sandstone and shale of the mid-Cretaceous Kuskokwim Group locally intruded by mafic dikes or sills (Rutledge, 1948; Hoare and Cobb, 1977; Box and others, 1993).
  • Age = Post mid-Cretaceous, the age of the host sedimentary rocks. The mineralization may be Late Cretaceous or Early Tertiary, the age of widespread intermediate to felsic igneous activity in the region (Box and others, 1993).
  • Age = Host rock is Pre Campanian - Post Barremian.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Bethel

Comments on the production information

  • Production Notes = About 2,000 pounds of cinnabar concentrates were recovered during placer mining operations on Rainy Creek (BH002), mostly below the mouth of Arsenic Creek.

Comments on the workings information

  • Workings / Exploration = In 1947, the U. S. Bureau of Mines completed 1,500 feet of dozer trenching and 1,440 feet of hand trenching, and collected 19 samples in the area of known lode mineralization (Rutledge, 1948).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013390
USGS Alaska Resource Data File ARDF BH001

Bibliographic references

  • Deposit

    Rutledge, F.A., 1948, Investigations of the Rainy Creek mercury prospect, Bethel district, Kuskokwim region, southwestern Alaska: U.S. Bureau of Mines Report of Investigations 4361, 7 p.

  • Deposit

    Hoare, J.M., and Cobb, E.H., 1977, Mineral occurrences (other than mineral fuels and construction materials) in the Bethel, Goodnews, and Russian Mission quadrangles, Alaska: U.S. Geological Survey Open-File Report 77-156, 98 p.

  • Deposit

    Frost, T.P., 1990, Geology and geochemistry of mineralization in the Bethel quadrangle, southwestern Alaska, in Goldfarb, R. J., Nash, J. T., and Stoeser, J. W., eds., Geochemical studies in Alaska by the U.S. Geological Survey, 1989: U.S. Geological Survey Bulletin 1950, p. C1-C9.

  • Deposit

    Box, S.E, Moll-Stalcup, E.J., Frost, T.P., and Murphy, J.M., 1993, Preliminary geologic map of the Bethel and southern Russian Mission quadrangles, southwestern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2226-A, 20 p., scale 1:250,000.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Bethel quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-455, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Rutledge, 1948

General comments

Subject category Comment text
Deposit Model Name = Epithermal mercury.

Reporter information

Type Date Name Affiliation Comment
Reporter 24-MAR-01 Travis L. Hudson Applied Geology