Unnamed (on the Yentna Glacier)

Occurrence in Alaska, United States with commodities Copper, Molybdenum

Geologic information

Identification information

Deposit ID 10308445
Record type Site
Current site name Unnamed (on the Yentna Glacier)

Geographic coordinates

Geographic coordinates: -151.68083, 62.73653 (WGS84)
Relative position Reed and others (1978, locality 28) show the location of mineralized cobbles in moraine along the west limit of the Yentna Glacier in the northeast quarter of Section 34, T. 31 N, R. 13 W., of the Seward Meridian within Denali National Park and Preserve. This site is located approximately two and a half miles north-northeast of TL057.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary

Materials information

Materials Type of material
Chalcopyrite Ore
Molybdenite Ore
Pyrite Ore

Mineral occurrence model information

Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2
Model code 80
USGS model code 21b
Deposit model name Porphyry Mo, low-F

Nearby scientific data

(1) -151.68083, 62.73653

Comments on the geologic information

  • Geologic Description = Granodiorite cobbles with fractures containing molybdenite, pyrite and minor chalcopyrite found at this site on the Yentna Glacier moraine are probably derived from the middle Tertiary (38 m.y.) Foraker pluton (Reed and others, 1978; Reed and Nelson, 1980). Minor malachite staining in Paleozoic sedimentary rocks is noted near the pluton contact. Further information that supports the Foraker pluton as the source of the float is anomalous copper (300 to 700 ppm) in a stream sediment and glacial debris sample taken from a site on the Yentna Glacier which drains the Foraker pluton (Curtin, Karlson, O'Leary, Day, and McDougal,1978). Use of a porphyry for this occurrence is not to suggest that a cobble with mineralized fractures is in itself a porphyry deposit. Instead, its possible affiliation with the Mt. Foraker pluton suggests that these veins could be a distal feature related to a concealed porphyry system. Not enough data exists to quantify this determination (Reed and others, 1978). This site is located approximately two and a half miles north-northeast of TL057 on the Yentna Glacier moraine.
  • Age = Middle Tertiary; mineralization is interpreted to be related to the 38 m.y. Foraker pluton (Reed and Nelson, 1980).

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Yentna

Comments on the workings information

  • Workings / Exploration = Reconnaissance mapping and rock sampling are all that have been done here (Reed and Nelson, 1980). Minor malachite staining in Paleozoic sedimentary rocks is noted near the pluton contact. Further information that supports the Foraker pluton as the source of the float is anomalous copper (300 to 700 ppm) in a stream sediment and glacial debris sample taken from a site on the Yentna Glacier which drains the Foraker pluton (Curtin, Karlson, O'Leary, Day, and McDougal,1978).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF TL056

Bibliographic references

  • Deposit

    Curtin, G.C., Karlson, R.C., O'Leary, R.M., Day, G.W., and McDanal, S.K., 1978, Geochemical and generalized geologic maps showing the distribution and abundance of gold and silver in the Talkeetna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-E, 2 sheets, scale 1:250,000.

  • Deposit

    Reed, B.L., Nelson, S.W., Curtin, G.C., and Singer, D.A., 1978, Mineral resources map of the Talkeetna Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-D, 1 sheet, scale 1:250,000.

  • Deposit

    Reed, B.L., and Nelson, S.W., 1980, Geologic map of the Talkeetna quadrangle: U.S. Geological Survey Miscellaneous Investigations Map I-1174, scale 1:250,000.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = Reed and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Possibly related to Porphyry Cu-Mo (Cox and Singer, 1986; model 21a) or Porphyry Mo, Low-F (Cox and Singer, 1986; model 21b).
Deposit Other Comments = This site is within Denali National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-AUG-98 Madelyn A. Millholland Millholland & Associates