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Idaho

Prospect in Alaska, United States with commodities Silver, Copper, Lead, Tin, Zinc, Fluorine-Fluorite, Tungsten
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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 10308734
Record type Site
Current site name Idaho

Geographic coordinates

Geographic coordinates: -167.1804, 65.44627 (WGS84)
Relative position The Idaho prospect is located on the east bank of Lost River just below the mouth of Tin Creek. This is about 4 miles upstream of the mouth of Lost River on the Bering Sea and 1.9 miles downstream from the Lost River Mine (TE048-TE051). This is locality 7 of Cobb and Sainsbury (1972). Cobb (1975) summarized relevant references under the name 'Idaho'.

Site location context

Political divisions (FIPS codes)

Nome(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Teller B-5(quadrangle 1:63,360 scale)

Teller SE(quadrangle 1:100,000 scale)

Teller(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Imuruk Basin(hydrologic unit)

Norton Sound(hydrologic accounting unit)

Northwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Diomede Native 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
Copper Primary
Lead Primary
Tin Critical Primary
Zinc Critical Primary
Fluorine-Fluorite Critical Secondary
Tungsten Critical Secondary

Materials information

Materials Type of material
Cassiterite Ore
Chalcopyrite Ore
Galena Ore
Sphalerite Ore
Stannite Ore
Calcite Gangue
Fluorite Gangue
Idocrase Gangue
Magnetite Gangue
Pyrite Gangue
Pyrrhotite Gangue

Alteration

  • All of the veining in the area can be considered a type of alteration in the outer fringes of a significant hydrothermal system. This includes fluorite, laminar magnetite-fluorite-idocrase, and the sulfide-rich veins. Dolomitization is also locally devloped but it is not known how this is related to mineralization.

Mineral occurrence model information

Model code 43
USGS model code 14b
Deposit model name Sn skarn

Nearby scientific data

(1) Oyl
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Idaho prospect is on a low bench (about 200 feet elevation ) on the east bank of Lost River. Here Ordovician limestone in the hanging wall of the Rapid River fault is locally exposed along cut banks of Lost River and its east tributary Tin Creek. Extensive fluorite veining in the limestone merges northward across Tin Creek to that exposed in the Lost River Valley prospect. The original Idaho prospect was a small area of chalcopyrite-pyrrhotite-fluorite mineralization exposed on the east bank of Lost River (Knopf, 1908). Sainsbury noted the presence of tin, sulfide minerals, and fluorite (1969, plate 1) and of beryllium rock and sulfides in this general area (1969, plate 5). Three types of mineralization are present here (Hudson, 1990): (1) fluorite and beryllium-bearing veins and replacements in dolomite; (2) magnetite-fluorite-idocrase (?) replacement veins (laminar skarn or wrigglite) along fractures in the carbonate rocks; and (3) sulfide-rich veins (and replacements?). Dolomite outcrops along the south side of lower Tin Creek contain irregularly sheeted fluorite veins. Individual veins are up to 3 inches wide and zones up to 1 foot wide can have up to 20 thin veinlets. Channel and grab samples of this mineralization contain up to 19% fluorine and 0.023 to .063 % beryllium. The presence of 0.023% beryllium in 4-foot wide zones containing sparse fluorite veins suggests that some of the mineralization is disseminated. Laminar magnetite-fluorite-idocrase (?) replacement veins (wrigglite) are common in outcrop along the east bank of Lost River. These veins, which vary from hairline seams to 3 feet wide, contain elevated tin, tungsten, beryllium, fluorine, base-metal, and silver. Five samples (Hudson 1983; 1990) contained 0.14 to 0.36% tin, 0.06 to 0.26% tungsten, 0.012 to 0.029% beryllium, 13 to 15% fluorine, and 0.3 to 4.7 ppm silver. Zinc, determined in only one of these samples, was 1.05%. Highly oxidized sulfide-rich mineralization is present in a vein exposed in a dozer trench on the east bank of Lost River. The trench exposes a 4-foot wide oxidized zone that strikes northeast and dips south. Sulfide remnants in this zone are massive pyrrhotite-chalcopyrite-sphalerite rock with minor constituents such as fluorite. Four sulfide-rich samples contained up to 0.19% tungsten, 0.64 to 3.72% copper, 0.14 to 14.3% zinc, 5 to 35 ppm silver, and weakly anomalous tin and lead (Hudson, 1983; 1990). Airborne and ground magnetometer surveys show that a large, 600+ gamma positive magnetic anomaly is centered on the Idaho prospect area. This feature combined with the widespread surface mineralization and alteration, the results of a soil geochemistry survey, and structural setting (interpreted to be in a downdropped hanging wall block of the Rapid River fault) suggests the presence of significant skarn and/or replacement mineralization at depth (Hudson, 1983; 1990). A vertical diamond drill hole was
  • Geologic Description = drilled in 1995 to test this interpretation. This drill hole was collared slightly east of the sulfide vein exposed in the dozer trench. It reached a total depth of 983 feet (Drechsler, 1995). It encountered sulfide-bearing veins, veinlets, and disseminations in the upper 100 feet including one interval between 40.5 and 45 feet that contained up to 50% massive pyrrhotite and chalcopyrite. Steep dipping magnetite-calcsilicate veins and veinlets, less than 1 inch wide and commonly less than 0.25 inch wide, are common below 100 feet. These appear to increase in intensity below 500 feet including two intervals (640 to 678 feet and 938 to the bottom of the hole) that are stockworks. Fluorite-bearing veins are scattered through the hole but appear to be more abundant at depth. Two thin (0.25 and 0.75 inch wide) felsic dikes are present between 910 and 930 feet. The sulfide-rich interval between 40.5 and 45 feet assayed 1.74% copper, 2.2% zinc, 16 ppm silver, 3.79% CaF2, 250 ppm tin, and 55 ppm tungsten. Other selected intervals in the hole were anomalous in base metals, tin, and tungsten but significant grades were not intercepted. Two five-foot samples representing the interval between 432 and 442 feet contained 340 and 650 ppm tin and 540 and 320 tungsten; a sample representing the 715 to 720 foot interval contained 11% fluorite, 160 ppm tin, and 375 ppm tungsten; and two five-foot samples representing the interval between 818 and 828 feet contained 10 and 11% fluorite, 520 and 640 ppm tin, and 480 and 510 ppm tungsten.
  • Age = The age of the mineralization is assumed to be related to the development of tin systems in the Lost River area and therefore Late Cretaceous, the age of the tin-mineralizing granites there (Hudson and Arth, 1983).

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Active

Mining district

District name Port Clarence

Comments on the reserve resource information

  • Reserves = Not defined

Comments on the workings information

  • Workings / Exploration = One dozer trench, a surface soil geochemical survey, outcrop geologic mapping and sampling, an airborne magnetic survey, a ground magnetic survey, and one vertical 983-foot diamond drill hole have been completed on the prospect.

Reference information

Bibliographic references

  • Deposit

    Knopf, Adolph, 1908, Geology of the Seward Peninsula tin deposits, Alaska: U.S. Geological Survey Bulletin 358, 71 p.

  • Deposit

    Cobb, E.H., and Sainsbury, C.L., 1972, Metallic mineral resource map of the Teller quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-426, 1 sheet, scale 1:250,000.

  • Deposit

    Sainsbury, C.L., 1972, Geologic map of the Teller quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Map I-685, 4 p., 1 sheet, scale 1:250,000.

  • Deposit

    Hudson, T.L., and Arth, J. G., 1983, Tin-granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.

  • Deposit

    Hudson, T.L., 1990, The Idaho deposits, Seward Peninsula, Alaska: Anchorage, Alaska, unpublished report to Barbara Winkley.

  • Deposit

    Drechsler, J.S., Jr., 1995, Diamond drill hole summary (hole 1), Idaho prospect at Lost River, Seward Peninsula, Alaska: Anchorage, Alaska, unpublished report to Barbara Winkley, 14 p.

  • Deposit

    Cobb, E.H., 1975, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Teller quadrangle, Alaska: U.S. Geological Survey Open-File Report 75-587, 130 p.

  • Deposit

    Hudson, T.L., 1983, Interim report on the Lost River district, Seward Peninsula, Alaska: Anchorage, Alaska, Anaconda Minerals Company internal report (Report held by Cook Inlet Region, Inc., Anchorage, Alaska).

  • Deposit

    Sainsbury, C.L., 1969, Geology and ore deposits of the central York Mountains, western Seward Peninsula, Alaska: U.S. Geological Survey Bulletin 1287, 101 p.

Comments on the references

  • Primary Reference = Hudson, 1983; Hudson, 1990; Drechsler, 1995

General comments

Subject category Comment text
Deposit Model Name = Skarn, vein, and replacement in limestone. Tin skarn (model 14b) and/or replacement tin (model 14c) model of Cox and Singer (1986) may be applicable
Deposit Model Number = 14b, 14c

Reporter information

Type Date Name Affiliation Comment
Reporter 10-MAY-1998 Travis L. Hudson Applied Geology

Beyond USGS

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

Maps centered on this site

Authoritative Alaska resources

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