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Jyro

Occurrence in Alaska, United States with commodities Silver, Gold, Arsenic, Copper, Mercury, Lead, Zinc
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10308136
Record type Site
Current site name Jyro
Alternate or previous names Bloomer Peak

Geographic coordinates

Geographic coordinates: -160.56881, 55.21813 (WGS84)
Relative position The map site of this occurrence is at an elevation of 1,100 feet on the northeast spur of Bloomer Peak. The site is 4,000 feet northeast of the top of the peak (Wilson and others, 1988, locality 36). Location is accurate to within 500 feet.

Site location context

Political divisions (FIPS codes)

Aleutians East(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Port Moller A-2(quadrangle 1:63,360 scale)

Unga Island(quadrangle 1:100,000 scale)

Port Moller(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Cold Bay(hydrologic unit)

Aleutian Islands(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Unga Corporation(ANCSA Village)

ANCSA Village NTVPIC(Type of land area)

NTVPIC(Federal land areas administered by NTVPIC)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Arsenic Critical Secondary
Copper Secondary
Mercury Secondary
Lead Secondary
Zinc Critical Secondary

Materials information

Materials Type of material
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Alteration includes silicification and minor argillization.

Mineral occurrence model information

Model code 105
USGS model code 25a-d
Deposit model name Epithermal vein, generic
Mark3 model number 119

Nearby scientific data

(1) -160.56881, 55.21813
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Peterson and opthers (1982) described small quartz veins near Bloomer Peak that assayed as much as 3.90 ppm gold. Followup led to the discovery of the Jyro vein system and numerous other quartz veins and silicified zones. The host rock is porphyritic quartz-feldspar tuff of the late Eocene to early Oligocene Popof volcanics (Wilson and others, 1995). The Jyro vein system crops out on the crest of Bloomer Peak. It stikes N60E and can be followed on the surface for 3,000 feet. It is a vein-quartz breccia averaging 12 feet wide, and forms the core of the mineralized system. It is broken and iron stained and exhibits at least three periods of silicification (Peterson and others, 1982). The tuff hostrock intensely silicified, iron stained and locally argillized as much as 200 feet from the vein system. Some of the altered tuff contains quartz veins and stringers as much as 4 inches thick. The Jyro vein and enclosing silicified tuff are sporadically enriched in gold. Grab samples contained as much as 0.62 ppm gold and 1.1 ppm silver, and trench samples as much as 0.31 ppm gold. Mean assay values of samples from the trench were 0.041 ppm gold, 0.225 ppm silver, 2.8 ppm molybdenum, 83 ppm arsenic, 0.145 ppm mercury, and 65 ppm Cu+Pb+Zn (Peterson and others, 1982). Small quartz veins elsewhere in the area assayed as much as 6.4 ppm gold. Battle Mountain Exploration Company mapped and sampled the site in 1990. They determined that the northeast-trending veins and northwest-trending faults are consistently anomalous in gold, with values from 0.5 to 5.0 ppm. Arsenic values ranged from 50 to 900 ppm and mercury values were as much as 2 ppm (Ellis and Apel, 1990).
  • Age = Eocene or younger.

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the workings information

  • Workings / Exploration = In 1982 UNC Teton Exploration Drilling Company mapped the site, cut 300 feet of trenches, collected 47 grab and 60 trench channel samples, and conducted a VLF-EM survey. Grab samples contained as much as 0.62 ppm gold and trench samples as much as 0.31 ppm gold. The U.S. Geological Survey collected a sample of the deposit (82ASH 27) in the mid-1980's. Battle Mountain Exploration Company mapped and sampled it in 1990. Gold values in their samples generally ranged from 0.5 to 5.0 ppm (Ellis and Apel, 1990).

Reference information

Bibliographic references

  • Deposit

    Peterson, R.J., Lemmers, J., Handverger, P., Gallagher, J., Pilcher, R., East, J., Macleod, T., Bartels. E., 1982, Geology and precious metals potential Unga, Popof, and Korovin Islands, Shumagin Group, Aleutian Chain, Alaska: UNC Teton Exploration Drilling Company report, 127 p., 5 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Angeloni, L.M., Wilson, F.H., and Sutlet, S., 1985, Map and tables showing preliminary rock geochemical data, Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 85-470, 179 p., 1 map sheet, scale 1:250,000.

  • Deposit

    Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., scale 1:250,000.

  • Deposit

    Ellis, W.T., and Apel, R.A., 1990, Unga/Alaska Peninsula 1990 final report, Battle Mountain Exploration Company report, 49 p., 29 map sheets at various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 map sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Peterson and others, 1982

General comments

Subject category Comment text
Deposit Model Name = Epithermal gold veins (Cox and Singer, 1986; model 25)
Deposit Other Comments = This site is on land patented by, or interim-conveyed to, the Aleut Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 13-JAN-01 S.H. Pilcher U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.