Gable Mountain

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu
Other commodities Mo; W
Ore minerals chrysocolla; malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale A-5
Latitude 59.07
Longitude -136.53
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is in Glacier Bay National Park and Preserve at an elevation of about 4,500 feet; it is on a rugged ridge about 0.6 miles southeast of the summit of Gable Mountain. It is in west-central part of section 29, T. 32 S., R. 53 E. of the Copper River Meridian. This location corresponds to number 75 on Plate 3 of Brew and others (1978). Location 14 on Plate 1 of MacKevett and others (1971) and location 4 of Cobb (1972; MF-424) appear to refer to the same occurrence but are shown approximately 1 mile to the northwest of the summit of Gable Mountain. Because of the discrepancies between different authors regarding the location of this occurrence, it should probably be considered accurate only to within about 1 mile.

Geologic setting

Geologic description

The following description is summarized from Brew and others (1978).
At site 1 at an elevation of 4,475 feet, there is a 0.7-foot-wide shear zone which has quartz stringers and copper stains. Below the shear zone there is quartz diorite float that has joint coatings of malachite and chrysocolla. Joint coatings of iron sulfide are reported in quartz diorite at a second site 8,000 - 9,000 feet to the southeast (but the plotted location is about 3,000 - 4,000 feet to the southwest). At site 1, a composite grab sample contained 1,000 ppm copper; a channel sample across the 0.7-foot-wide shear zone contained 250 ppm copper and 7 ppm silver. At Site 2, 7 grab samples contained up to 970 ppm copper, 3 ppm silver, 200 ppm molybdenum, and 150 ppm tungsten. Based on the Cretaceous age of the intrusion (Brew and others, 1978), the mineralization must be Cretaceous or younger in age.
Geologic map unit (-136.531879568449, 59.0696160050714)
Mineral deposit model There is too little information to assign a model type.
Age of mineralization The deposit must be Cretaceous or younger in age based on the Cretaceous age of the intrusion that hosts it (Brew and others, 1978).

Production and reserves

Indication of production None

Additional comments

The deposit is within Glacier Bay National Park and Preserve where exploration and development is restricted.

References

MRDS Number A013118

References

Reporters T.C. Crafford (T. Crafford & Associates, Anchorage)
Last report date 2/4/2001