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Moly Dike

Occurrence in Alaska, United States with commodities Molybdenum, Silver, Copper, Manganese, Lead, Tin, Tungsten
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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 10308505
MRDS ID A013467
Record type Site
Current site name Moly Dike
Alternate or previous names McLeod
Related records 10308504, 10002524

Geographic coordinates

Geographic coordinates: -159.29137, 63.27439 (WGS84)
Relative position This occurrence is at the southwestern end of the Kaiyuh Mountains, 11.25 miles southeast of Blackburn, an abandoned settlement on the Yukon River. The occurrence is at an elevation of 1150 feet, approximately 250 feet northeast of hill 1170, in the SW1/4 sec. 32, T. 25 S., R. 3 W., Kateel River Meridian. It is approximately 1500 feet north of the caved trenches at the original McLeod prospect (UL003). The location is accurate within 300 feet.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Unalakleet B-1(quadrangle 1:63,360 scale)

Ophir SW(quadrangle 1:100,000 scale)

Unalakleet(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Federal lands

Innoko National Wildlife Refuge(National Wildlife Refuge)

National Wildlife Refuge FWS(Type of land area)

FWS(Federal land areas administered by FWS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Molybdenum Primary
Silver Secondary
Copper Secondary
Manganese Critical Secondary
Lead Secondary
Tin Critical Secondary
Tungsten Critical Secondary

Comments on the commodity information

  • Ore Material = ferrimolybdenite

Materials information

Materials Type of material
Chalcopyrite Ore
Molybdenite Ore
Pyrite Ore
Ferrimolybdite Ore

Alteration

  • (Local) The principal mineralized dike is pervasively sericitized and locally intensely silicified. The bedded rocks peripheral to the stock are thermally altered to hornfels and contain secondary pyrite and chlorite.

Mineral occurrence model information

Model code 80
USGS model code 21b
Deposit model name Porphyry Mo, low-F

Host and associated rocks

  • Host or associated Host
    Rock type
    Stratigraphic age (oldest) Early Cretaceous

Nearby scientific data

(1) -159.29137, 63.27439
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = This occurrence consists of molybdenite-bearing quartz veinlets in a weakly to moderately developed quartz-stockwork zone exposed in frost-riven rubble in an area of about 100 by 1000 feet. The mineralization is hosted by a suite of quartz-feldspar-porphyritic granite dikes that trend 330 degrees across hill 1170 in a swath about 400 feet wide. Individual dikes are up to 100 feet thick. Molybdenite and ferrimolybdenite are concentrated in the northernmost dike, which is highly sericitized and pervasively cut by locally molybdenite-bearing quartz veinlets that form parallel arrays and local stockworks (Bressler and others, 1979). The molybdenite occurs as discrete, platy aggregates along the margins of the quartz veinlets and as very fine grained disseminations in the quartz, imparting a distinct blue-gray color to the veinlets. Vein density ranges from 1 veinlet to more than 15 veinlets per square foot; they are mostly concentrated along the southern contact of the northernmost dike. The molybdenum content of this deposit ranges between 0.01 and 0.09% molybdenum (Bressler and others, 1979).? the country rocks in the general area of this occurrence include poorly sorted, medium- to coarse-grained arkosic sandstone and subordinate siltstone, shale, and lesser intermediate to mafic volcanic rocks. The strata generally strike northwest with gentle dips to the northeast and southwest (Bressler and others, 1979). The dikes occur along the western lobe of a Cretaceous or Tertiary granitic stock composed of 20-40% bipyramidal to subhedral quartz and 10-30% feldspar phenocrysts in a matrix mostly of quartz and feldspar. Pyrite is a minor accessory (<1%), along with rare chalcopyrite; there are no mafic minerals. The outcrop area of the stock measures about 6000 by 2500 feet, and is elongate to the northeast. The exposure is centered along the boundary of sections 32 and 33, and the stock sends dike swarms into sections 4 and 28 (Bressler and others, 1979). A younger suite of biotite-quartz-feldspar porphyritic dikes exposed south of the McLeod prospect apparently does not occur at this site (Bressler and others, 1979).? Also see UL003 and UL005.
  • Age = Late Cretaceous or Tertiary, the age of the granitic stock and its apophyses.
  • Age = Cretaceous or Tertiary, the presumed age of the mineralized felsic intrusive hostrock.
  • Age = Host rock is Tertiary - Cretaceous.

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Kaiyuh

Comments on the workings information

  • Workings / Exploration = Surface exploration and mapping was conducted by Bear Creek Mining Company in 1976 (Fields, 1976), and by WGM, Inc., on behalf of Doyon, Ltd., in 1979 and 1980 (Bressler and others, 1979; Lessman, 1979). Airborne and radiometric surveys were completed in 1980 (Boniwell, 1981 [DR 81-05]; Boniwell, 1981 [DR 81-08]). A 3500- by 2700-foot molybdenum soil anomaly was defined; this anomaly is open to the southwest.

Reference information

Bibliographic references

  • Deposit

    Fields, E.D., 1976, Regional mineral survey of the Kaltag withdrawal area (Doyon, Ltd.) and examination of the McLeod molybdenum prospect, Kaltag, Alaska: Doyon Report 76-21, 9 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

  • Deposit

    Lessman, J., 1979, Doyon project 1979 annual progress report: Doyon Report 79-31, 5 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

  • Deposit

    Bressler, J., Cleveland, G., Ruzicka, J., 1979, 1979 annual progress report McLeod project area: Doyon Report 79-33, 48 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

  • Deposit

    Boniwell, J.B., 1981, Airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-05, 9 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

  • Deposit

    Boniwell, J.B., 1981, An addendum to the report on airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-08, 16 sheets. (Report held by Doyon, Ltd., Fairbanks, Alaska.)

Comments on the references

  • Primary Reference = Bressler and others, 1979

General comments

Subject category Comment text
Deposit Model Name = Porphyry Mo (Cox and Singer, 1986; model 16a and 21b)
Deposit Model Number = 16a, 21b
Deposit Other Comments = This property is on Doyon, Ltd. selected lands. For more information, contact Doyon, Ltd., in Fairbanks, Alaska.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-AUG-2001 S.S. Dashevsky Northern Associates Inc.

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.