1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Pyramid

Prospect in Alaska, United States with commodities Copper, Molybdenum, Silver, Gold, Lead, Antimony, Zinc
Map
XML
JSON
KML
A
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Ore body information
  13. Controls for ore emplacement
  14. Economic information about the deposit and operations
  15. Mining district
  16. Reserves and resources
  17. Links to other databases
  18. Bibliographic references
  19. General comments
  20. Reporter information

Geologic information

Identification information

Deposit ID 10308987
MRDS ID A010658
Record type Site
Current site name Pyramid
Alternate or previous names Pyramid Prospect, Pyramid Mountain Copper Prospect

Geographic coordinates

Geographic coordinates: -160.67244, 55.62924 (WGS84)
Relative position This prospect is located on the Alaska Peninsula on the southeast flank of Pyramid Mountain approximately 4 miles northwest of Balboa Bay (Christie, 1974, color anomaly 90; MacKevett and Holloway, 1977, locality 6; Nokleberg and others, 1987, locality AP6; Wilson and others, 1988, locality 6; Young and others, 1997, locality 36). The map site is at an elevation of about 1,200 feet, in the S1/2 of sec. 35, T. 52 S., R. 74 W., of the Seward Meridian. The location is accurate.

Site location context

Political divisions (FIPS codes)

Aleutians East(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Port Moller C-3(quadrangle 1:63,360 scale)

Port Moller(quadrangle 1:100,000 scale)

Port Moller(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Cold Bay(hydrologic unit)

Aleutian Islands(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Shumagin Corporation(ANCSA Village)

ANCSA Village NTVPIC(Type of land area)

NTVPIC(Federal land areas administered by NTVPIC)

Geographic areas

Country State
United States Alaska

Public Land Survey System information

Meridian Township Range Section Fraction State
Seward 52S 74W 35 S1/2 Alaska

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary
Silver Secondary
Gold Secondary
Lead Secondary
Antimony Critical Secondary
Zinc Critical Secondary

Materials information

Materials Type of material
Chalcocite Ore
Chalcopyrite Ore
Covellite Ore
Molybdenite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • The alteration consists of a barren, potassically-altered core zone, an intermediate zone characterized by pervasive quartz and sericite, and a propylitic outer zone.

Mineral occurrence model information

Model code 54
USGS model code 17
Deposit model name Porphyry Cu (North America)
Mark3 model number 81
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

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite

Nearby scientific data

(1) -160.67244, 55.62924
ListMap

Economic information

Ore body information

  • General form Well-defined concentric alteration zones.

Controls for ore emplacement

  • Center of mineralization within quartz diorite porphyry pluton.

Comments on the geologic information

  • Geologic Description = The Pyramid copper-molybdenum deposit is associated with a quartz diorite pluton that cuts Paleocene to Eocene sedimentary rock of the Tolstoy Formation (Wilson and others, 1995). The stock has been dated at 6 million years (Wilson and others, 1996). The prospect is a classic copper-molybdenum deposit having a potassic core surrounded by a phyllic zone and an outer propylitic zone. The central potassic core contains secondary biotite after mafic minerals and 2 to 10 percent magnetite as fracture fillings and disseminated clots and grains. The core, entirely in the intrusive, is roughly 800 by 1,700 feet. It is essentially barren, with total sulfide content less than 0.25 percent and copper and molybdenum values in the 0.00X percent range (Christie, 1975). The phyllic zone is characterized by sericite, quartz, and andalusite in a zone surrounding the potassic core. It occurs mostly in the intrusive rocks and measures 700 to 2,500 feet in width. The propylitic zone is characterized
  • Geologic Description (cont)= by chlorite, magnetite, epidote, and calcite. The highest total sulfide content (5 to 10 percent) occurs in the inner part of the propylitic zone and outer part of the quartz-sericite zone. Pyrite:chalcopyrite ratios are 50:1 or greater and are associated with copper grades of 0.15 percent or less (Christie, 1975). Toward the inner part of the phyllic zone pyrite:chalcopyrite ratios decrease and copper grades increase to 0.3 to 0.4 percent; molybdenum grades are 0.03 to 0.04 percent. In this copper-rich part of the system the sulfides occur as disseminations and thin fracture fillings. The deposit has been oxidized to depths of 0 to 450 feet and exhibits a blanket of secondary copper enrichment as much as 300 feet thick. The enriched zone contains chalcocite and covellite, as well as some chalcopyrite. The best grades of copper, as much as 0.8 percent, occur in the upper 100 feet of the blanket. The thickest enrichment zones are not necessarily associated with the thickest
  • Geologic Description (cont)= zones of oxidation. Lead, antimony, and zinc are also reported in some assays. The Quintana-Duval-Aleut Joint Venture mapped, sampled, and drilled this deposit in 1974 and 1975. They diamond-drilled 19 holes for a total of 5,565 feet. As a result of this work they outlined an estimated resource of 126,000,000 tons of ore grading 0.403 percent copper and 0.025 percent molybdenum. Potential exists for another 49 million tons of chalcocite-enriched ore (Christie, 1975).
  • Alteration = The alteration consists of a barren, potassically-altered core zone, an intermediate zone characterized by pervasive quartz and sericite, and a propylitic outer zone.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic
Significant Yes

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Reserves and resources

  • Type In-situ
    Estimate year 1985
    Total resources 56000mt ore
    Commodity Subtype Grade units Group Importance Year
    Molybdenum Mo 0.03 wt-pct Molybdenum Primary 1985
    Copper Cu 0.4 wt-pct Copper Primary 1985
  • Type In-situ
    Estimate year 2008
    Total endowment 159000000mt ore
    Remarks Singer, 2008 in PorCuEX2008.xls.
    Commodity Subtype Grade units Group Importance Year
    Copper 0.372 wt-pct Copper Primary 2008
    Gold 0.05 g/mt Gold Secondary 2008
    Molybdenum 0.018 wt-pct Molybdenum Primary 2008

Comments on the reserve resource information

  • Reserves = The resource is estimated at 126 million tons of ore averaging 0.403 percent copper and 0.025 percent molybdenum. There is potential for an additional 49 million tons of chalcocite-enriched ore.

Comments on the workings information

  • Workings / Exploration = Quintana-Duval mapped, sampled, and diamond-drilled 19 holes totalling 5,565 feet in 1974-1975. The U.S. Geological Survey sampled the deposit in the 1980s.

Reference information

Bibliographic references

  • Reserve-Resource

    Eakins, G.R., Bundtzen, T.K., Robinson, M.S., Clough, J.G., Green, C.B., Clautice, K.H., and Albanese M.A., 1983, Alaska's mineral industry, 1982, Alaska Division of Geological and Geophysical Surveys Special Report 31, 63 p.

  • Deposit

    Wolfhard, F.H., 1974, Pyramid prospect preliminary evaluation: Unpublished Quintana Minerals Corporation report, 9 p., 6 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • General

    Unpublished information from the USGS BORA-MRDS files.

  • Deposit

    Wolfhard, F.H., 1976, Final report, Pyramid project 1976 work: Unpublished Quintana Minerals Corporation report, 2 p. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Armstrong, R.L., Harakal, J.E., and Hollister, V.F., 1976, Age determinations of late Cenozoic porphyry copper deposits of the North American Cordillera: Institute of Mining and Metallurgy Transactions, Section B, v. 85, p. 239-244.

  • 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

    Eakins, G.R., Bundtzen, T.K., Robinson, M.S., Clough, J.G., Green, C.B., Clautice, K.H., and Albanese M.A., 1983, Alaska's mineral industry, 1982, Alaska Division of Geological and Geophysical Surveys Special Report 31, 63 p.

  • Deposit

    Freeport Exploration Company, 1985, 1984 report of activities, Canoe Bay joint venture: Freeport Exploration Company, 25 p. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Angeloni, L.M., Wilson, F.H., and Sutlet, S., 1985, Map and tables showing preliminary rock geochemical data, Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 85-470, 179 p., 1 map sheet, scale 1:250,000.

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

  • Deposit

    Bundtzen, T.K., Green, C.B., Deagen, J., and Daniels, C.L., 1987, Alaska's mineral industry, 1986: Alaska Division of Geological and Geophysical Surveys, Special Report 40, 68 p.

  • 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., 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

    Wilson, F.H., White, W.H., Detterman, R.L., and Case, J.E., (1991) 1996, Maps showing the resource assessment of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska Peninsula, with a section on Geology of the Pyramid porphyry copper deposit, Alaska Peninsula, Alaska, by W.H. White, J.S. Christie, M.R. Wolfhard, and F.H.Wilson, and a section on Description of the Shumagin epithermal gold vein deposit, by W.H. White and L.D. Queen: U.S. Geological Survey Miscellaneous Field Studies Map MF-2155-F, 46 p., 2 sheets, scales 1:500,000 and 1:250,000.

  • Deposit

    Young, L.E., St. George, P., and Bouley, B., 1997, Porphyry copper deposits in relation to the magmatic history and palinspastic restoration of Alaska, in Goldfarb, R.J., and Miller, L.D., (eds.), Mineral deposits of Alaska: Economic Geology Monograph 9, p. 306-333.

  • Deposit

    Christie, J.S., and Wolfhard, M.R., 1977, Pyramid porphyry copper-molybdenum prospect, Alaska: Geol. Assoc. of Canada, Annual Meeting, 1977, Program with Abstracts, Vol. 2, p. 12.

  • Deposit

    Cobb, E.H., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and West-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 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, 39 p., 1 sheet, scale 1:1,000,000.

  • Deposit

    Bundtzen, T.K., Eakins, G.R., Green, C.B., and Lueck, L.L., 1986, Alaska's mineral industry 1985: Alaska Division of Geological & Geophysical Surveys Special Report 39, 68 p.

  • Deposit

    Christie, J.S., 1975, Pyramid Project, Aleut-Quintana-Duval joint venture report on 1975 drill program: Quintana Minerals Report, 17 p. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • 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 = Christie, J.S., 1975, Pyramid Project, Aleut-Quintana-Duval joint venture report on 1975 drill program: Quintana Minerals Report, 17 p. (Report held by the Aleut Corporation, Anchorage, Alaska.)

General comments

Subject category Comment text
Deposit Other Comments = This prospect is on land selected or patented by, or interim-conveyed to, the Aleut Corporation.
Age Age = Six million years or younger.

Reporter information

Type Date Name Affiliation Comment
Reporter 03-JAN-01 S.H. Pilcher U.S. Geological Survey
Reporter 01-APR-84 Elliott, R.L. U.S. Geological Survey
Reporter 01-MAY-87 Leonard, Kenneth R. (Huber, Donald F.) U.S. Geological Survey

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.