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

Geologic information

Identification information

Deposit ID 10308370
Record type Site
Current site name J-26
Alternate or previous names July 26, June 26

Geographic coordinates

Geographic coordinates: -143.28372, 63.98173 (WGS84)
Relative position The J-26 prospect encompasses about 4 square miles on a hilltop, in sections 4 and 5, T. 25 N., R. 11 E., of the Copper River Meridian and sections 32 and 33, T. 26 N., R. 11 E., of the Copper River Meridian. The location is accurate, and the coordinates given in the fields above correspond to the approximate center of the prospect.
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Geographic areas

Country State
United States Alaska


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

Materials information

Materials Type of material
Quartz Gangue


  • (Local) The alteration consists of widespread propylitic alteration and localized silica alteration and skarn (DiMarchi and others, 1989).

Mineral occurrence model information

Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2

Nearby scientific data

(1) -143.28372, 63.98173

Comments on the geologic information

  • Geologic Description = J-26 is a porphyry molybdenum prospect within a rhyolite porphyry; it is located near the margin of a propylitized, medium-grained, biotite- and hornblende-bearing, quartz monzonite stock. Nearby pelitic schist, calc-silicate schist, and marble have been recrystallized to hornfels, calc-silicate tactite and garnet-pyroxene skarn. There are numerous Tertiary (?) mafic and felsic dikes, as well as quartz veins. Alteration at the prospect consists of widespread propylitic alteration, localized silica alteration, and skarn (DiMarchi and others, 1989). The general geology consists of Tertiary felsic volcanics surrounded by Mesozoic granitic rocks (Foster, 1970). The property has been soil sampled. Elements listed above as commodities were found in anomalous concentrations in soil samples (Doyon Ltd., 1998).
  • Age = Likely to be one of the three porphyry events in eastern interior Alaska at 90 to 100 Ma, 70 Ma, or 55 Ma.

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Active

Mining district

District name Fortymile

Comments on the workings information

  • Workings / Exploration = Surface exploration and soil sampling have been done on the property by companies working under an exploration agreement with Doyon Ltd.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF TC011

Bibliographic references

  • Deposit

    Foster, H.L., 1970, Reconnaissance geologic map of the Tanacross quadrangle, Alaska: U.S. Geological Survey Miscellaneous Geological Investigations Map I-593, 1 sheet, scale 1:250,000.

  • Deposit

    DiMarchi, J.J., Flanders, R.W., Freeman, L.K., Puchner, C.K., Rohtert, W.R., Stubbs, G.S., and Tolbert, R.S., 1989, 1989 annual report, Alaska field operations, volume 1: Central Alaska Exploration Corporation, 203 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

  • Deposit

    Doyon, Limited, 1998, Veta Prospects 1997 Volume 1: Fairbanks, Alaska, Doyon, Limited., unpublished report 98-10, 256 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

Comments on the references

  • Primary Reference = Doyon Ltd., 1998

General comments

Subject category Comment text
Deposit Model Name = Mo-porphyry (Cox and Singer, 1986; model 21a)
Deposit Other Comments = This prospect lies on Doyon Ltd. selected land. For more information, contact Doyon Ltd.

Reporter information

Type Date Name Affiliation Comment
Reporter 13-APR-99 Cameron, C.E. Alaska Division of Geological and Geophysical Surveys