Unnamed (east of upper Illinois Creek)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Pb; Zn
Other commodities Cu
Ore minerals galena; hemimorphite; malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale NL
Quadrangle map, 1:63,360-scale A-4
Latitude 64
Longitude -157.8
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence, locally called 'Airstrip Sinter,' is located near the north end of the Illinois Creek airstrip (not shown on the 1953/1966 Ophir A-4 topographic map). The site is 0.4 mile north-northeast of the top of hill 988, in the NE1/4 sec. 2, T. 17 S., R. 5 E., Kateel River Meridian. The location is accurate within 5 miles.

Geologic setting

Geologic description

This occurrence is a 1-meter-thick quartz vein that trends northeast across the northern end of the Illinois Creek mine airstrip. The vein cuts silty gray limestone and contains blebs and pockets of crystalline galena and possibly hemimorphite, locally accompanied by malachite staining. Soil sampling shows anomalous lead values coincident with the trend of vein float. A vein sample contained 0.3-1.0% lead, 1.0-3.0% zinc, and 30-100 ppm copper (Flanigan, 1998).
Geologic map unit (-157.802433112026, 63.9993477040422)
Mineral deposit model Pb-Zn vein (Cox and Singer, 1986; model 22c?)
Mineral deposit model number 22c?
Age of mineralization Flanigan (1998) interprets this occurrence to be related to magmatic fluids from the Khotol pluton, based on its proximity to the pluton and its low molybdenum content . K-Ar and Ar/Ar dates for the Khotol pluton are approximately 110 Ma (Flanigan, 1998).
Alteration of deposit Oxidation of copper mineral.

Production and reserves

Workings or exploration This occurrence was discovered by Anaconda Minerals Company in 1980 (Flanigan, 1998). The vein was exposed by bulldozer work on the Illinois Creek airstrip.
Indication of production None

References

MRDS Number 10307898

References

Flanigan, B., 1998, Genesis and mineralization of ore deposits in the Illinois Creek region, west central Alaska: University of Alaska, Fairbanks, M.Sc. thesis, 125 p., 2 plates.
Reporters C.E. Cameron (Northern Associates Inc.)
Last report date 8/7/2001