Glen Ridge No. 1

Prospects, Inactive

Alternative names

Skookona

Commodities and mineralogy

Main commodities Ag; Au
Other commodities As; Mo; Pb; Sb; W
Ore minerals arsenopyrite; azurite; galena; gold; limonite; pyrite; scheelite
Gangue minerals quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5689
Longitude -150.7615
Nearby scientific data Find additional scientific data near this location
Location and accuracy
This site represents several prospects on the crest of an unnamed ridge 0.7 mile east-northeast of Glacier Peak. The prospects are known as the Glen Ridge No. 1 (Cobb, 1980 [OFR 80-363]) or Skookona (Wells, 1933). They occupy a sizeable area in the NE1/4 SW1/4 section 36, T. 15., R. 17 W., Fairbanks Meridian. The location is accurate.
The prospects correspond to location 19 of Cobb (1972 [MF 366]), and are included with other nearby prospects in location 15 of MacKevett and Holloway (1977). They are included in location 48 of Bundtzen, Smith, and Tosdal (1976), comprise mineral deposit 230 of Hawley and Associates (1978), and correspond to number 53 of Bundtzen (1981), and number 74 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The country rock in the area of the Glen Ridge prospects is mainly metafelsite of the lower Paleozoic Spruce Creek sequence (Bundtzen, 1978). The site is near a fault that strikes NNW and slightly offsets the metafelsite. The area also contains Birch Creek Schist, which appears to be juxtaposed against Spruce Creek metafelsite along a NE-trending fault (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, fig. K-2, and occurrence 74, v. 2).
Two types of deposits occur at the prospects. One consists of argentiferous and auriferous, pyrite- and galena-bearing, quartz veins that occupy a shear zone that strikes NNW. Poorly exposed lenticular veins, as much as 40 feet thick and 150 feet long, occur in the shear zone. These veins were described by Capps (1919, p. 100; Moffit, 1933, p. 333-34, and Wells, 1933, p. 373) as rusty or iron-stained quartz that contains pyrite, galena, and, rarely, free gold.
The other type consists of mineralized quartz-tourmaline veins that contain arsenopyrite, pyrite, scheelite, galena, and sphalerite. The veins occupy a steeply-dipping shear zone that strikes N45E (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 74). Some of these veins contain moderately high values of silver and gold. Bundtzen, Smith, and Tosdal (1976) collected a sample of an arsenopyrite-rich vein that assayed 0.28 ounce of gold per ton and 16.3 ounces of silver per ton. Samples of tourmaline-bearing veins assayed a trace to 0.23 ounce of gold per ton, 8.07 to 13 ounces of silver per ton, 5.05 to 7.45 percent arsenic, about 1 percent lead, and up to 150 ppm tungsten, 71 ppm molybdenum, and 405 ppm antimony (Thornsberry, McKee, and Salisbury, 1984, v. 2, nos. 14123 and 14124).
Geologic map unit (-150.76378392971, 63.5683978730471)
Mineral deposit model Polymetallic veins and low-sulfide Au-quartz (tourmaline) veins? (Cox and Singer, 1986; models 22c and 36a?).
Mineral deposit model number 22c and 36a?
Age of mineralization The deposit is assumed to be Eocene (see record MM091).
Alteration of deposit Extensive silicification along NNW faults; introduction of silica and tourmaline on NE shear zones. Oxidation of copper and iron minerals.

Production and reserves

Workings or exploration Some of the area was prospected at least as early as 1916, when the veins were discovered (Capps, 1919). Development work included a series of pits. The property has been inactive since 1985.
Indication of production None

Additional comments

The prospects are in Denali National Park and Preserve.

References

MRDS Number A011216

References

Bundtzen, T.K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p.
Reporters C.C. Hawley
Last report date 1/29/2001