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  3. Mineral Resource Data System (MRDS)

Unnamed (west of upper Illinois Creek)

Occurrence in Alaska, United States with commodities Silver, Zinc, Gold
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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. Host and associated rocks
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. Reporter information

Geologic information

Identification information

Deposit ID 10307901
Record type Site
Current site name Unnamed (west of upper Illinois Creek)

Geographic coordinates

Geographic coordinates: -157.9401, 64.04843 (WGS84)
Relative position This site consists of two occurrences, informally called Madelyn's gossan and Nate's gossan. Madelyn's gossan is located near the summit of locally-named 'Survey Ridge,' a prominent, east-west-trending ridge about a mile west of upper Illinois Creek. For this record, the site is plotted at an elevation of 1000 feet, near the center of the N1/2 of sec. 5, T. 17 S., R. 5 E., Kateel River Meridian. The location is accurate within 2 miles. Nate's gossan is approximately 1.2 miles east-northeast of Madelyn's gossan.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Nulato A-4(quadrangle 1:63,360 scale)

Nulato SE(quadrangle 1:100,000 scale)

Nulato C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Zinc Critical Primary
Gold Secondary

Materials information

Materials Type of material
Malachite Ore
Pyrite Ore
Limonite Gangue

Alteration

  • (Local) Sulfides are oxidized to limonite, and, locally, to malachite (Flanigan, 1998).

Host and associated rocks

  • Host or associated Associated
    Rock type
    Rock unit name Khotol
    Stratigraphic age (youngest) Early Cretaceous
    Chronological age 112
    Dating method Ar-Ar
    Stratigraphic age (youngest) Early Cretaceous
    Chronological age 108
    Dating method K-Ar

Nearby scientific data

(1) -157.9401, 64.04843
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Madelyn's gossan consists of sparse, limonitic, quartzite float. Samples contain 10-20% banded limonite after pyrite. Analyses of four rock samples show only slightly anomalous values, including up to 226 ppm zinc, 2.3 ppm silver, and 30 ppb gold (Flanigan, 1998). Nate's gossan is a small outcrop (10 by 50 meters) of limonitic, brecciated quartzite. The limonite replaces banded and veined sulfides (pyrite?). Traces of malachite occur in nearby graphitic schist. Four rock samples contained up to 80 ppm copper, 308 ppm zinc, 1.0 ppm silver, and 25 ppb gold (Flanigan, 1998).
  • Age = the nearby Khotol pluton has been dated by K-Ar and Ar/Ar methods at 108-112 Ma (Flanigan, 1998). Flanigan links these occurrences to magmatic fluids from that pluton.
  • Age = Chronological age is for the nearby Khotol pluton.

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Probably inactive

Mining district

District name Kaiyuh

Comments on the workings information

  • Workings / Exploration = These occurrences were discovered by Anaconda Minerals Company in 1980; geologic mapping and sampling followed (Flanigan, 1998).

Reference information

Bibliographic references

  • Deposit

    Flanigan, B., 1998, Genesis and mineralization of ore deposits in the Illinois Creek region, West Central Alaska: University of Alaska, Fairbanks, M.Sc. thesis, 125 p., 2 plates.

Comments on the references

  • Primary Reference = Flanigan, 1998

Reporter information

Type Date Name Affiliation Comment
Reporter 07-AUG-01 Cameron, C.E. Northern Associates Inc.

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.