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Step Mountain

Prospect in Alaska, United States with commodities Lead, Zinc, Silver, Cadmium
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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. Mineral occurrence model information
  8. Nearby scientific data
  9. Economic information about the deposit and operations
  10. Mining district
  11. Links to other databases
  12. Bibliographic references
  13. General comments
  14. Reporter information

Geologic information

Identification information

Deposit ID 10307411
Record type Site
Current site name Step Mountain
Alternate or previous names Wk

Geographic coordinates

Geographic coordinates: -141.40781, 65.5238 (WGS84)
Relative position The Step Mountain prospects cover about 5 square miles and are located in sections 7-9, 17, 18, and 20, T. 8 N., R. 31 E., of the Fairbanks Meridian, just to the north of Step Mountain. The coordinates are for the approximate center of the area. The location is accurate. These prospects are located within Doyon, Limited selected or conveyed land.

Site location context

Political divisions (FIPS codes)

Southeast Fairbanks(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Charley River C-1(quadrangle 1:63,360 scale)

Charley River NE(quadrangle 1:100,000 scale)

Charley River(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Federal lands

Doyon, Limited(ANCSA Region)

ANCSA Region NTVPIC(Type of land area)

NTVPIC(Federal land areas administered by NTVPIC)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Lead Primary
Zinc Critical Primary
Silver Secondary
Cadmium Secondary

Materials information

Materials Type of material
Galena Ore
Hydrozincite Ore
Smithsonite Ore
Calcite Gangue
Quartz Gangue

Mineral occurrence model information

Model code 228
USGS model code 32b
Deposit model name Mississippi Valley, Appalachian Zn
Mark3 model number 42

Nearby scientific data

(1) -141.40781, 65.5238
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Step Mountain Pb-Zn prospects are in a doubly plunging antiform that forms a dome-shaped mountain. The Permian Step Conglomerate and the Nation River Formation are exposed at its core. A northwest- or west-trending fault cuts the center of Step Mountain and may host additional mineralization (Northstar Exploration, Inc., 1999). The zinc minerals consist of smithsonite, a light gray to white oxide mineral that is not believed to be an alteration product of sulfides, and hydrozincite. The lead mineral is galena (Doyon, Limited, 1986). The lead and zinc minerals are in quartz veins(?) in Permian limestone breccia zones and lenses, in fossiliferous calcareous siltstone, and in layers overlying fossiliferous calcarenite, where it locally replaces coquina in an upper packstone unit (Mosher, 1990; Schmidt, 1997). Along the crest of the anticline, the conglomerate, sandstone, and cross-cutting quartz veins contain only slightly anomalous base-metal values (Northstar Exploration, Inc., 1999). Vitrinite reflectance data from the Devonian Nation River Formation and the Mississippian Ford Lake Shale in the Step Mountain antiform suggest that these rocks were exposed to temperatures of approximately 240 to 285 degrees Celsius (Underwood and others, 1992). There are an estimated 35,000 to 850,000 tons of economic grade Zn, which includes 4.9 meters of 2.7 percent Zn, 3.6 meters of 18.8 percent Zn, and 40 cm of 19.7 percent Zn (Northstar Exploration, Inc., 1999). This prospect was discovered in the late 1970s and has been explored by short trenches and diamond drilling (Northstar Exploration, Inc., 1999).
  • Age = Permian or younger.

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Active

Mining district

District name Black

Comments on the reserve resource information

  • Reserves = There are an estimated 35,000 to 850,000 tons of economic grade Zn, which includes 4.9 meters of 2.7 percent Zn, 3.6 meters of 18.8 percent Zn, and 40 cm of 19.7 percent Zn (Mosher, 1990).

Comments on the workings information

  • Workings / Exploration = The prospects have been examined since the late 1970s, and several short trenches and some diamond drilling have been completed (Northstar Exploration, Inc., 1999).

Reference information

Bibliographic references

  • Deposit

    Doyon, Limited, 1986, Mines, prospects, and geochemical anomalies on Doyon, Limited, regional overselection lands, Alaska: Fairbanks, Alaska, Doyon, Limited, Report 86-01A, v. 1, 150 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

  • Deposit

    Underwood, M.B., Brocculeri, T., Bergfeld, D., Howell, D.G., and Pawlewicz, M., 1992, Statistical comparison between illite crystallinity and vitrinite reflectance, Kandik region of east-central Alaska: U.S. Geological Survey Bulletin 2041, p. 222-237.

  • Deposit

    Schmidt, J.M., 1997, Shale-hosted Zn-Pb-Ag and barite deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska, 1997: Economic Geology Monograph 9, p. 35-65.

  • Deposit

    Northstar Exploration, Inc., 1999, 1998 Annual Report Kandik, Block 7: Fairbanks, Alaska. (Report held by Doyon, Limited, Fairbanks, Alaska.)

  • Deposit

    Mosher, Greg, 1990, Step Mountain project, Geological exploration and diamond drilling, 1990: Pasminco Exploration Ltd. for Doyon, Limited, unpublished report 92-77, 19 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

Comments on the references

  • Primary Reference = Northstar Exploration, 1999

General comments

Subject category Comment text
Deposit Model Name = Carbonate-hosted Zn-Pb (Schmidt, 1997; Cox and Singer, 1986; model 32b)
Deposit Other Comments = These prospects lie on Doyon, Limited selected or conveyed land. For more information, contact Doyon, Limited.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-APR-00 Cameron, C.E. Alaska Division of Geological and Geophysical Surveys

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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