Unnamed (northwest of the terminus of Chistochina Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Zn
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-2
Latitude 63.2066
Longitude -144.8715
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is northwest of the 1966 terminus of the Chistochina Glacier at an elevation of about 5,200 feet. The occurrence is in the SE1/4SE1/4 section 4, T. 20 S., R. 15 E., Fairbanks Meridian. It corresponds to locality 17 on figure 1 of Rose (1967)and locality 8 on figure 6 of Cobb (1979 [OFR 79-238]) and is approximately the same as locality 133 in table 2 of Nokleberg and others (1991). The location is accurate within 0.2 mile.

Geologic setting

Geologic description

The rocks in this area are part of the Eagle Creek Formation of Early Permian age and consist of interlayered argillite and limestone (Nokleberg and others, 1991). The unit was mapped as Mankomen Formation by Rose (1967). Subsequently, the units were remapped as part of the Eagle Creek Formation, a member of the Mankomen Group (Richter and Dutro, 1975).
The Eagle Creek argillite is extensively pyritized at the site. The pyritized argillite lies north of a body of Upper Triassic (?) ultramafic rock that is intruded by quartz monzonite of Mesozoic age (Rose, 1967).
A grab sample of pyritic argillite contained 0.02 ounce of gold per ton and trace amounts of silver and zinc (Rose, 1967).
Geologic map unit (-144.873729926055, 63.2062047178684)
Age of mineralization Post-Early Permian and probably Mesozoic, related to a nearby granodiorite intrusion.
Alteration of deposit Pyritization of Lower Permian argillite.

Production and reserves

Workings or exploration Geologic mapping and limited surface sampling.
Indication of production None