Unnamed (lower Ruby Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Pb
Other commodities Au
Ore minerals galena; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5577
Longitude -150.8266
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurence is at an elevation of about 2650 feet in lower Ruby Creek, a tributary of Yellow Creek. It is in the SE1/4 NW1/4 section 3, T. 16 S., R. 17 W., Fairbanks Meridian. The location is accurate within 300 feet. The occurrence represents the location of rock sample 209 of Hawley and Associates (1978), and appears not to have been described previously.

Geologic setting

Geologic description

A major fault that strikes NNW controls the course of Yellow Creek; strata to the east are apparently downthrown. This occurrence is in quartz schist in marble of the Spruce Creek sequence in the downthrown block. (Bundtzen, 1981; Hawley and Associates, 1978; Thornsberry, McKee, and Salisbury, 1984, fig. K-2). The occurrence consists of altered quartzite that contains galena and pyrite. A representative chip sample of mineralized quartz schist contained 1.8 percent lead, 60 ppm silver, and 0.3 ppm gold (Hawley and Associates, 1978, sample no. 209). Stream-sediment samples (nos. 202 and 203) collected upstream of the locality are weakly anomalous in lead, zinc, and silver.
Geologic map unit (-150.828884776978, 63.5571964781782)
Mineral deposit model Polymetallic replacement deposit (Cox and Singer, 1986; model 19a).
Mineral deposit model number 19a
Age of mineralization The deposit is assumed to be Eocene (see record MM091).
Alteration of deposit Silicified and sulfidized quartz schist in marble.

Production and reserves

Workings or exploration Hawley and Associates (1978) collected rock and stream-sediment samples in 1976. There are no workings.
Indication of production None

Additional comments

The occurrence is in Denali National Park and Preserve.