Dent Point

Occurrence in Alaska, United States with commodities Silver, Gold, Copper, Arsenic, Molybdenum, Lead, Zinc

Geologic information

Identification information

Deposit ID 10308209
Record type Site
Current site name Dent Point

Geographic coordinates

Geographic coordinates: -159.79244, 55.84925 (WGS84)
Relative position This occurrence is located on the Alaska Peninsula on the ridge land between Ramsey Bay and Grub Gulch (Christie, 1974, color anomaly 81; MacKevett and Holloway, 1977, locality 3; Wilson and others, 1988, locality 3). The map site is at an elevation of about 2,000 feet, 0.35 mile northeast of the top of hill 2704, in the S1/2 of sec. 23, T. 50 S., R. 69 W., of the Seward Meridian. The location is accurate to within 2 miles.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary
Arsenic Secondary
Molybdenum Secondary
Lead Secondary
Zinc Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Gold Ore
Molybdenite Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Quartz Gangue

Alteration

  • (Local) The rocks exhibit argillic, phyllic, and propylitic alteration.

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4
Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2
Model code 78
USGS model code 20c
Deposit model name Porphyry Cu-Au
Mark3 model number 34

Nearby scientific data

(1) -159.79244, 55.84925

Comments on the geologic information

  • Geologic Description = This occurrence is marked by a color anomaly measuring approximately 2,000 by 5,000 feet (Christie, 1974). The area contains Miocene to Pliocene volcanic rocks cut by small granodiorite and diorite intrusives (Wilson and others, 1995). The rocks exhibit argillic, phyllic, and propylitic alteration. Hornblende collected from some of the volcanic rocks from the general area gave ages of 5 million to 6 million years (Wilson and others, 1994). Trace amounts of chalcopyrite and molybdenite are present in fractures in hornfels and in quartz veins cutting medium-grained diorite. A zone of highly fractured quartz latite and latite porphyry contains pyrite veins as much as 0.25 inch thick. Agglomerate containing pods of large, euhedral pyrite crystals have been noted (Butherus and others, 1979). Other sulfide minerals reported include galena, pyrrhotite, and sphalerite. Some of the volcanic rocks contain quartz veins as much as 4 inches thick. The earliest known investigation of this area was by Eakins (1970), who collected stream-sediment samples containing as much as 300 ppm copper. Many of the rocks collected by Butherus and others (1979) contained anomalous copper values, and some also carried anomalous amounts of gold, lead, silver, and zinc. A sample of a siliceous andesite dike contained 0.3 ppm gold and 1.4 ppm silver. Soils contained as much as 0.8 ppm gold and 0.9 ppm silver. Pan concentrates contained as much as 0.5 ppm gold and 1.3 ppm silver. Stream-sediment samples collected by the U.S. Geological Survey contained as much as 150 ppm copper, 50 ppm lead, 50 ppm molybdenum, and 0.5 ppm silver; and pan concentrates contained as much as 700 ppm copper, 150 ppm molybdenum, 15,000 ppm lead, 2,000 ppm zinc, and 70 micrograms gold per pan (Frisken, 1992). Rock samples contained as much as 100 ppm copper, 0.042 ppm gold, 100 ppm lead, and 20 ppm molybdenum (Arbogast and others, 1987).
  • Age = Miocene or younger.

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the workings information

  • Workings / Exploration = The occurrence was sampled in 1974 by an Aleut-Quintana-Duval joint venture (Christie, 1974). The area was mapped and sampled by Resource Associates of Alaska (Butherus and others, 1979). The U.S. Geological Survey examined and sampled the area in the mid-1980's (Wilson and others, 1988).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SB003

Bibliographic references

  • Deposit

    Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Hollister, V.F., 1978, Geology of the porphyry copper deposits of the Western Hemisphere; New York, Society of Mining Engineering, American Institute of Mining, Metallurgy, and Petroleum Engineers Incorporated, 218 p.

  • Deposit

    Butherus, D.L, Gressitt, E.E., Pray, J., Corner, N.G., Lindberg, P.H., and Fankhauser, R.E., 1979, Exploration and evaluation of the Aleut Native Corporation lands; Volume III: Resource Associates of Alaska, 69 p. 90 sheets, various sacales. (Report held by the Aleut Native Corporation, Anchorage, Alaska.)

  • Deposit

    Arbogast, B.F., Bailey, E.A., and Frisken, J.G., 1987, Analytical results and sample locality maps of stream sediment, heavy-mineral-concentrate, and rock samples from the Port Moller, Stepovak Bay, and Simeonof island quadrangles, Alaska: U.S. Geological Survey Open-File Report 87-502, 122 p., 2 sheets, scale 1:250,000.

  • Deposit

    Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., scale 1:250,000.

  • Deposit

    Wilson, F.H., Shew, N., DuBois, G.D., and Bie, S.W., 1994, Sample locality map and analytical data for potassium-argon ages in the Port Moller, Stepovak Bay and Simeonof Island quadrangles, Alaska Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2155-E, 18 p., 1 map sheet, scale 1:250,000.

  • Deposit

    Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 map sheet, scale 1:250,000.

  • Deposit

    Eakins, G.R., 1970, Mineralization near Stepovak Bay, Alaska Peninsula, Alaska: Alaska Division of Mines and Geology Special Report 4, 12 p.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = Butherus and others, 1979

General comments

Subject category Comment text
Deposit Model Name = Porphyry Cu, Porphyry Cu-Mo, Porphyry Cu-Au (Cox and Singer, 1986; models 17, 21a, 20c)
Deposit Model Number = 17, 21a, 20c
Deposit Other Comments = This site is on lands selected by the Aleut Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 31-OCT-00 S.H. Pilcher U.S. Geological Survey