Unnamed (on western side of Brooks Mountain)

Prospect in Alaska, United States with commodities Lead, Uranium

Geologic information

Identification information

Deposit ID 10308420
Record type Site
Current site name Unnamed (on western side of Brooks Mountain)

Geographic coordinates

Geographic coordinates: -167.15641, 65.52827 (WGS84)
Relative position This area is along the west contact zone of the Brooks Mountain granite stock, about 0.8 mile north of the prospects on the southwest side of the stock (TE055). The prospect area is at an elevation of about 2,500 feet along and immediately west of the continental divide. This locality was not shown separately by Cobb and Sainsbury (1972) but some relevant references were summarized by Cobb (1975) under the name 'Brooks Mtn.'.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Lead Secondary
Uranium Secondary

Materials information

Materials Type of material
Galena Ore
Calcite Gangue
Idocrase Gangue
Tourmaline Gangue

Alteration

  • (Local) Tactite in carbonate rocks, quartz-tourmaline veining in granite, and secondary oxide development.

Mineral occurrence model information

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

Host and associated rocks

  • Host or associated Associated
    Rock unit name Brooks Mountain
    Chronological age 77
    Uncertainty 3
    Stratigraphic age (youngest) Late Cretaceous

Nearby scientific data

(1) -167.15641, 65.52827

Comments on the geologic information

  • Geologic Description = Brooks Mountain granite stock is a 1 by 2 mile composite intrusion just south and east of Brooks Mountain (elevation 2,898 feet), the highest part of the York Mountains. The country rocks to the Late Cretaceous (77.0 +/- 3.0 my; Hudson and Arth, 1983, p. 769) Brooks Mountain granite are Ordovician limestone and locally fine-grained, carbonaceous metaclastic rock of unknown but probable Paleozoic age. Tactite is common in marble nearby to the granite contact on the northwest and southwest sides of the stock (Sainsbury, 1969, plate 1). Hornfels is developed in the nearby metaclastic rocks. The granite is dominately seriate and prophyritic types (Hudson and Arth, 1983, p. 770) that are not known to be directly linked with significant tin metallization in the western Seward Peninsula tin belt; they are instead precusor-type granites (Hudson and Reed, 1997, figure 3). Tactite here contains much idocrase and some tourmaline. It forms irregular masses and green-colored seams along fractures in marble. Small cubes of galena are present in open vugs in the tactite. About 700 feet to the southeast, the Brooks Mountain granite contains 1 to 4 inch wide quartz-tourmaline veins along joints. Uranium (to 1% eU) is present in zuenerite associated with hematite coatings on vein and fracture surfaces (West and White, 1952).
  • Age = the age of the mineralization is assumed to be similar to the age of the Brooks Mountain granite (77.0 +/- 3.0 my; Hudson and Arth, 1983, p. 769).
  • Age = Chronological age is for Brooks Mountain.

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name Port Clarence

Comments on the reserve resource information

  • Reserves = Not defined

Comments on the workings information

  • Workings / Exploration = Some surface pits have been dug here.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF TE056

Bibliographic references

  • Deposit

    West, W.S., and White, M.G., 1952, The occurrence of zeunerite at Brooks Mountain, Seward Peninsula, Alaska: U.S. Geological Survey Circular 214, 7 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

    Cobb, E.H., 1975, Tungsten occurrences in Alaska: U.S. Geological Survey Mineral Investigations Resource Map MR-66, 1 sheet, scale 1:250,000.

  • Deposit

    Patton, T.L., and Robinson, M.S., 1975, Bedrock geology, geochemistry, and geophysics of Brooks Mountain, Seward Peninsula, Alaska: University of Alaska, Fairbanks, M.Sc. thesis, 106 p.

  • 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., and Reed, B.L., 1997, Tin deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 450-465.

  • 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.

  • 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.

Comments on the references

  • Primary Reference = West and White, 1952

General comments

Subject category Comment text
Deposit Model Name = This is an area of variable contact metamorphism of Ordovician limestone by the Brooks Mountain granite stock. Possibly tin skarn (Cox and Singer, 1986; model 14b)

Reporter information

Type Date Name Affiliation Comment
Reporter 10-MAY-98 Travis L. Hudson Applied Geology