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Saddle

Prospect in Alaska, United States with commodities Zinc, Lead
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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. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10307798
Record type Site
Current site name Saddle

Geographic coordinates

Geographic coordinates: -154.34796, 63.40549 (WGS84)
Relative position The Saddle prospect occurs in the divide between Nixon Fork and Soda Creek drainages and about 1.3 miles (2 km) north of Reef Ridge deposit in Section 13, T. 22 S., R. 22 E., of the Kateel River Meridian. Location is precisely known to within 100 feet (30 meters).

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Medfra B-3(quadrangle 1:63,360 scale)

Medfra S(quadrangle 1:100,000 scale)

Medfra C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

North Fork Kuskokwim River(hydrologic unit)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

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
Zinc Critical Primary
Lead Secondary

Comments on the commodity information

  • Gangue = ferricrete
  • Gangue = secondary calcite

Materials information

Materials Type of material
Smithsonite Ore
Dolomite Gangue
Calcite Gangue

Alteration

  • (Local) Smithsonite and sulfide species altered to ferricrete by groundwater.

Mineral occurrence model information

Model code 224
USGS model code 32a
Deposit model name Mississippi Valley, S.E. Missouri Pb-Zn
Mark3 model number 42

Host and associated rocks

  • Host or associated Host
    Rock type
    Stratigraphic age (youngest) Silurian

Nearby scientific data

(1) DSwc
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Saddle prospect is underlain by a continuous sequence of laminated to thinly bedded, light to dark gray dolomite of the Lower to Middle Silurian Paradise Fork Formation (Dutro and Patton, 1982). Host units strike N 80 to 85 West and dip 55 degrees South. The bedded sequence hosting the smithsonite mineralization is underlain on the north and south by dolomitic shale beds of the Middle to Upper Telsitna Formation (Dutro and Patton, 1982). Mineralization occurs in a 10 foot ( 3m) wide by 20 feet (6 m) long Amphipora-bearing horizon of bedded dolomite containing smithsonite, secondary dolomite, ferricrete, and secondary calcite in solution breccia. Host rock age is Silurian, based on Amphipora sp. found in ore zone of Paradise Fork Formation (Blodgett, 1982). The age of the mineralization is unknown. . Soil sampling from surface exploration indicates a weak to moderate zinc anomaly extending in an east-west direction for about 1,200 feet (366 m). Three grab samples in the smithsonite-bearing solution breccia zone averaged 15.79 percent zinc with no appreciable lead (Schmidt, 1997).
  • Age = Host rock age is Silurian, based on Amphipora found in ore zone of Paradise Fork Formation (Blodgett, 1982). The age of the mineralization is unknown.

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = The Saddle prospect was discovered by WGM Inc. and Patino Ltd. during exploration for base metasls in the late 1970s. Intermittant exploration work was continued by Pasminco Ltd. until about 1989 (Schmidt, 1997). Soil sampling from surface exploration indicates a weak to moderate zinc anomaly extending in an east-west direction for about 1,200 feet (366 m). Three grab samples in the smithsonite-bearing solution breccia zone average 15.79 percent zinc and no appreciable lead (Schmidt, 1997).

Reference information

Bibliographic references

  • Deposit

    Patton, W.W., Jr., Moll, E.J., Dutro, J.T., Jr., Silberman, M.L., and Chapman, R.M., 1980, Preliminary geologic map of Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-A, 1 sheet, scale l:250,000.

  • Deposit

    Blodgett, R.B., 1982, Stratigraphy of Reef Ridge project area: WGM Inc., Anchorage, Alaska, Reef Ridge Project area, Block 10, Doyon region: 34 pages.

  • Deposit

    Dutro, T.T. Jr., and Patton,W.W. Jr., 1982, New Paleozoic Formations in the northern Kuskokwim Mountains, west-central Alaska: U.S. Geological Survey Bulletin 1529-H, p. H13-H22.

  • Deposit

    Anderson, G.M., and Macqueen, R.W., 1988, Mississippi Valley Type lead-zinc deposits, in Roberts, R.G., and Sheahan, P.A., eds., Ore deposit models: Geoscience Canada Reprint Series 3, Ottawa, Canada, p. 79-90.

  • 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.

Comments on the references

  • Primary Reference = Schmidt, 1997

General comments

Subject category Comment text
Deposit Model Name = Appalachian zinc (Cox and Singer ,1986; model no. 32b) or Mississippi Valley Type
Deposit Other Comments = See Soda Creek (MD056), Reef Ridge (MD055), Midway (MD046) and Bear Pass (MD044) prospects in Medfra Quadrangle.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-98 Bundtzen, T.K. Pacific Rim Geological Consulting

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.