Unnamed (west of upper Harris River)

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo; Pb; Zn
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale C-3
Latitude 55.50459
Longitude -132.8736
Nearby scientific data Find additional scientific data near this location
Location and accuracy This is the site of a hole that was diamond drilled in the early 70s. There were probably several more holes in the vicinity, and this site is at about the center of a block of claims explored by those holes that covered at least a square mile. The site is about 0.6 mile south-southeast of the center of section 25, T. 73 S., R. 82 E., and about 0.6 mile due east of peak 3344.

Geologic setting

Geologic description

This prospect is at the pad of a diamond drill hole put down by AlVenCo, Inc. in the early 1970s. There is at least one other hole nearby. The hole was drilled to test the presence of a probable buried, copper-molybdenum porphyry deposit (Frankhauser, 1969; Hedderly-Smith, 1999 [Inventory]). The prospective deposit underlies an area about a mile long and a half-mile wide that is oriented north-south. The area is geochemically anomalous and marked by extensive hornfelsing, disseminated pyrite, silicification and sericitization, and scattered occurrences of molybdenite. The rocks in the area consist of metamorphosed shale, sandstone, and andesite of the Luck Creek Breccia of Silurian or Ordovician age that are cut by several types of intermediate igneous rocks. The hole probably went into granodiorite a few hundred feet from the surface.
About 1,200 feet to the southeast, a zone about 8 feet in diameter of sheared and bleached andesite of the Descon Formation contains 50-75 percent pyrite (Hedderly-Smith, 1999 [Inventory]). A sample contained 706 parts per million (ppm) copper, 147 ppm lead, 2,142 ppm zinc, 29.1 ppm silver, and 2.557 ppm gold. Hedderly-Smith suggests that the intrusion that Alvenco drilled also has potential as a gold porphyry.
Geologic map unit (-132.875247785166, 55.5042339771618)
Mineral deposit model Porphyry copper-molybdenum-gold deposit (Singer and Cox, 1986; model 21a).
Mineral deposit model number 21a
Age of mineralization Probably related to a buried Cretaceous pluton.
Alteration of deposit Silicification, sericitization, hornfelsing, and bleaching of metavolcanic and metasedimentary rocks.

Production and reserves

Workings or exploration At least two diamond-drill holes were put down in the early 1970s; considerable surface prospecting took place then and in the 1990s.
Indication of production None

Additional comments

The land in the vicinity of this prospect has been identified for possible selection by the Sealaska Corporation.

References

References

Frankhauser, R., 1969, Pin Peak prosect: Alvenco Inc., 13 p. (Unpublished report held as file 6343, American Heritage Center, University of Wyoming, Laramie.)
Hedderly-Smith, D.A., 1992, Report on 1991 work in the Upper Harris River area-Sealaska minerals reconnaissance project: Sealaska Corporation, 12 p. plus plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1993, Report of the 1992 field season-Sealaska minerals reconnaissance project: Sealaska Corporation, 60 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1997, Report on the 1995 and 1996 work on the Kasaan Peninsula-Sealaska minerals project: Sealaska Corporation, 87 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1997, Results of the 1996 upper Harris River stream sediment sampling-Sealaska minerals reconnaissance project: Sealaska Corporation, 9 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1999, Inventory of metallic mineral prospects, showings and anomalies on Sealaska lands, 1988 through 1998: Sealaska Corporation, Juneau, Alaska, 217 p. (internal report held by Sealaska Corporation, Juneau, Alaska).
Reporters D.J. Grybeck (Applied Geology)
Last report date 5/1/2004