Glacier Fork

Occurrence, Inactive

Alternative names

Knik River - Glacier Fork

Commodities and mineralogy

Main commodities Ag; Au; Cu; W
Ore minerals chalcopyrite; pyrrhotite; scheelite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale AN
Quadrangle map, 1:63,360-scale C-4
Latitude 61.59
Longitude -148.2
Nearby scientific data Find additional scientific data near this location
Location and accuracy Near the headwaters of Glacier Fork of the Knik River, near western edge of unnamed glacier. Accurate within 2,500 ft. Locality M-13 of Richter (1967), locality 47 of Cobb (1972), and locality 36 of MacKevett and Holloway (1977).

Geologic setting

Geologic description

Abundant irregular quartz veins found in iron-stained metasedimentary rocks of the Late Cretaceous Valdez Group and in an adjacent Tertiary quartz diorite stock. The quartz veins contain pyrrohotite and small amounts of chalcopyrite. Assays of vein and float samples show 0.02 oz/ton Au and 0.08 to 0.26 oz/ton Ag (Richter, 1967).
Geologic map unit (-148.202217512728, 61.5894781516849)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization The veins are Tertiary or younger, based on geologic relationships.
Alteration of deposit Metasedimentary rocks are iron-stained (Richter, 1967).

Production and reserves

Workings or exploration Richter (1967) reported assays of vein and float samples show 0.02 oz/ton Au and 0.08 to 0.26 oz/ton Ag. Stream-sediment samples taken downstream contained scheelite.
Indication of production None

Additional comments

Cobb (1972) also notes four localities (110, 111, 112, and 113) spread along Glacier Fork. These all appear to be stream-sediment samples that contained scheelite. Deposit does not appear rich enough or large enough to warrant further prospecting (Richter, 1967).

References

MRDS Number A011648; D002741

References

Reporters D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS)
Last report date 7/30/1998