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Black Mountain

Prospect in Alaska, United States with commodity Tin
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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 10308745
Record type Site
Current site name Black Mountain

Geographic coordinates

Geographic coordinates: -166.7474, 65.48228 (WGS84)
Relative position The Black Mountain area is a four square mile upland between Tozer Creek and the California River, in the northern Teller B-4 quadrangle and adjacent parts of the Teller C-4 quadrangle. Large parts of this area are thermally metamorphosed and tactite is widespread. However, the prospect area described here is at about 1700 feet elevation on the southwest ridgecrest between headwaters to Constance Creek and an unnamed east tributary to Tozer Creek. This is locality 13 of Cobb and Sainsbury (1972). Cobb (1975) summarized relevant references under the name 'Black Mtn.'.

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-4(quadrangle 1:63,360 scale)

Teller SE(quadrangle 1:100,000 scale)

Teller C(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

Brevig Mission 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
Tin Critical Primary

Materials information

Materials Type of material
Cassiterite Ore
Galena Ore
Sphalerite Ore
Diopside Gangue
Epidote Gangue
Fluorite Gangue
Garnet Gangue
Idocrase Gangue
Plagioclase Gangue
Quartz Gangue
Tourmaline Gangue
Wollastonite Gangue

Alteration

  • Calc-silicate hornfels and tactite development is common; late quartz-fluorite +/- tourmaline veining and alteration is present along faults and fractures

Mineral occurrence model information

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

Nearby scientific data

(1) -166.7474, 65.48228
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The upland including Black Mountain is an area of hornfels, calc-silicate hornfels, and tactite intruded by a locally exposed biotite granite. The metasedimentary rocks, fine-grained metapelitic and metacarbonate rocks, are of unknown but probable Paleozoic age. The Late Cretaceous (79.1 +/- 2.9 my, Hudson and Arth, 1983, p. 769) biotiote granite, medium-grained and equigranular, is exposed in a small area on the southern flanks of the upland and is interpreted to be part of an early precurser granite phase rather than an mineralyzing granite phase (Hudson and Arth, 1983, p. 784; Hudson and Reed, 1997, figure 3). The wide distribution of thermally metamorposed rocks and the results of gravity and aeromagnetic surveys (McDermott, 1983a) indicate that most of the Black Mountain area is underlain by granite at depth. The area is transected by many normal faults and related fractures. Sainsbury and Hamilton (1967, p. B23) noted the presence of quartz-topaz greisen with cassiterite, pyrite, pyrrhotite, sphalerite, and galena in the northeast part of the exposed granite body but most of the mineralization and alteration in the area is associated with calc-silicate rocks. Calc-silicate rocks contain garnet, idocrase, tourmaline, wollastonite, and epidote. Cross-cutting veins and alteration along normal faults and fractures include quartz, tourmaline, fluorite, and sulfide minerals (pyrite, sphalerite, arsenopyrite, and probably others). Cassiterite and wolframite have not been conclusively identified in the calc-silicate rocks. Only reconnaissance geochemistry for a few rock samples is available (Sainsbury and Hamilton, 1967, p. B24; Hudson, 1984, p. 20). Tin is weakly anomalous in most tactite samples but one garnet-epidote-idocrase rock contained 1,800 ppm tin. Weak base metal, silver, and gold (60 and 100 ppb) and strong arsenic (400 ppm), fluorine (over 20,000 ppm), and boron (2,230 ppm) anomalies are present in some rocks.
  • Age = Late Cretaceous; the Black Mountain biotite granite, interpreted to be linked to alteration and mineralization in this area, has been determined to be 79.1 +/- 2.9 my old by the K/Ar method (Hudson and Arth, 1983, p. 769).

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Port Clarence

Comments on the workings information

  • Workings / Exploration = Some reconnaissance rock geochemistry and traverse geology, regional gravity and aeromagnetic surveys, and some onsite magnetic character and susceptability determinations have been completed (Hudson, 1984; McDermott, 1983a; 1983b; Reed and others, 1989).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Sainsbury and Hamilton, 1967; McDermott, 1983 (1982 geophysical report); Hudson, 1984

General comments

Subject category Comment text
Deposit Model Name = Tin skarn (Cox and Singer, 1986; model 14b).

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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