Canyon Creek

Occurrence, Inactive

Commodities and mineralogy

Main commodities Pb; Zn
Ore minerals limonite; pyrite; yellow sulfates

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.684
Longitude -150.6143
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 3300 feet, on an unnamed fork of Canyon Creek. The location is where the creek crosses the boundary between sections 22 and 23, T. 14 S., R. 16 W., Fairbanks Meridian. The location is accurate. The site corresponds to occurrence 98 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The Canyon Creek occurrence is in a graphitic schist unit of the upper Precambrian Birch Creek Schist (Bundtzen, 1981). The unit is about 340 feet thick, and is intercalated with garnet-mica-feldspar-quartz schist (Thornsberry, McKee, and Salisbury, 1984, v. 1, p. 158-161). The graphitic schist is commonly weathered to an orange-red color; protected areas are covered with a yellow sulfate(?) mineral efflorescence; and stream channels draining the unit are coated with iron oxide precipitate. Pyrite is disseminated in the graphitic unit, but valuable sulfide minerals have not been found.
The former presence of zinc in near-surface bedrock horizons is suggested by zinc geochemistry. Zinc content is less than 195 ppm in stream sediment collected immediately below the graphitic schist, but increases to as much as 540 ppm downstream. Stream pH is 3.5 immediately below the schist but becomes neutral downstream. Locally, lead is also anomalous; a stream-sediment sample collected from a tributary creek about 1 mile east of the occurrence contained 295 ppm lead (and 260 ppm zinc).
The graphitic unit was surveyed by EM and magnetic methods. The result of the EM survey is consistent with a response to a massive sulfide deposit; the result of the magnetic survey suggests that graphite is not the sole conductor (Thornsberry, McKee, and Salisbury, 1984).
Speculatively, the Canyon Creek occurrence conceals a buried stratabound sed-ex deposit of late Precambrian age.
Geologic map unit (-150.616594664503, 63.6835016372075)
Mineral deposit model Sedimentary-exhalative in graphitic schist.
Age of mineralization Possibly syngenetic sed-ex deposit of late Precambrian age.
Alteration of deposit Conspicuous oxidation and (or) leaching of iron and zinc minerals.

Production and reserves

Workings or exploration There are no workings. Geochemical and geophysical surveys were carried out in 1983 during a U.S. Bureau of Mines investigation (Thornsberry, McKee, and Salisbury, 1984).
Indication of production None

Additional comments

The Canyon Creek occurrence is in Denali National Park and Preserve.

References

References

Reporters C.C. Hawley
Last report date 2/5/2001