Fort Hamlin Hills pluton

Occurrence in Alaska, United States with commodities Rubidium, Tin, Tantalum, Tungsten

Geologic information

Identification information

Deposit ID 10307305
Record type Site
Current site name Fort Hamlin Hills pluton

Geographic coordinates

Geographic coordinates: -149.92314, 66.00965 (WGS84)
Relative position The occurrence is located about 24 miles west of Stevens Village along a high (approximately 2500-foot level) ridge in the Fort Hamlin Hills (sec. 29, T. 14 N., R. 11 W., of the Fairbanks Meridian). Location is accurate within a 1-mile radius.
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Geographic areas

Country State
United States Alaska


Commodity Importance
Rubidium Primary
Tin Primary
Tantalum Secondary
Tungsten Secondary

Materials information

Materials Type of material
Pyrite Ore
Hematite Gangue
Tourmaline Gangue


  • (Local) Secondary chlorite, sericite, tourmaline, hematite and pyrite.

Mineral occurrence model information

Model code 47
USGS model code 15b
Deposit model name Sn veins

Host and associated rocks

  • Host or associated Associated
    Rock unit name Fort Hamlin Hills
    Chronological age 109
    Uncertainty 3
    Stratigraphic age (youngest) Cretaceous

Nearby scientific data

(1) -149.92314, 66.00965

Comments on the geologic information

  • Geologic Description = This occurrence consists of a sample from a 5- to 8-ft.-wide tourmaline- and pyrite-bearing altered leucocratic, felsic dike which cuts biotite granite (Barker and Foley, 1986). The dike is variably stained brick-red and green and exposed for 50 feet along a north-trending strike. Alteration extends several feet into the granite, and secondary minerals in the dike and host granite include minor chlorite, sericite, tourmaline, hematite, and pyrite.
  • Age = the host dike cuts (and is probably related to) a biotite granite of the Fort Hamlin Hills pluton. The Fort Hamlin Hills pluton has not been dated, but its age is likely Cretaceous, based on ages of several compositionally similar plutons in the area which have ages ranging from 106 to 112 Ma (Barker, 1991).
  • Age = Chronological age is for compositionally similar plutons in the area.

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Yukon Flats

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF BV004

Bibliographic references

  • Deposit

    Barker, J.C., and Foley, J.Y., 1986, Tin reconnaissance of the Kanuti and Hodzana Rivers uplands, central Alaska: U.S. Bureau of Mines Information Circular 9104, 27 p.

Comments on the references

  • Primary Reference = Barker and Foley, 1986

General comments

Subject category Comment text
Deposit Model Name = Sn veins(?) (Cox and Singer, 1986; model 15b)
Deposit Other Comments = Occurrence consists of a single strongly anomalous sample. Sample number 181 (Barker and Foley, 1986) contained 308 ppm Sn, 1,102 ppm Rb, 29 ppm Ta, and 16 ppm W.

Reporter information

Type Date Name Affiliation Comment
Reporter 17-NOV-99 J. M. Britton U.S. Geological Survey