Poovookpuk Mountain

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Mo
Ore minerals chalcopyrite; malachite; molybdenite
Gangue minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale SL
Quadrangle map, 1:63,360-scale C-6
Latitude 63.45
Longitude -171.53
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site is on the east side of Poovookpuk Mountain in the headwaters of the Kookooliktook River, western St. Lawrence Island. It is centered on a small ridge between headwater tributaries at an elevation of about 600 feet. It is located within 1/2 mile and is locality 9 of Cobb (1972). Cobb (1980) summarized relevant references under the name 'Poovookpuk Mtn.'.

Geologic setting

Geologic description

A stock of quartz monzonite porphyry, 1/2 mile across, intrudes Cretaceous volcanic rocks and contains disseminated chalcopyrite, malachite, pyrite and minor molybdenite (Patton and Csejtey, 1971, p. C13). A grab sample contained 3,000 ppm copper but the molybdenum concentration in this sample was below detection (Patton and Csejtey, 1971, p. C8). Composite chip samples collected across the stock contained 700 ppm copper or less (Patton and Csejtey, 1971, p. C13). The Cretaceous volcanic rocks peripheral to the stock are heavily pyritized and extensively oxidized. The only sulfide mineral identified in the volcanic rocks is pyrite but a grab sample of massive pyritized rock contained 1,500 ppm copper, 10 ppm silver, and 30 ppm molybdenum. Fourteen stream sediment samples collected over about 1.5 miles of the nearby headwater drainages (Patton and Csejtey, 1972) contained anomalous to highly anomalous concentrations of copper (to 1,500 ppm), molybdenum (to 70 ppm), and silver (to 1.5 ppm). Alteration of the quartz monzonite porphyry has not been described but is probably present. The nearby volcanic rocks are probably also altered in addition to being pyritized.
Geologic map unit (-171.532774782301, 63.4490728261711)
Mineral deposit model Porphyry Cu-Mo? (Cox and Singer, 1986; model 21a?).
Mineral deposit model number 21a?
Age of mineralization Mid-Cretaceous, the age of K/Ar dated intrusive and volcanic rocks on western St. Lawrence Island (Patton and Csejtey, 1980).
Alteration of deposit Alteration of the quartz monzonite porphyry has not been described but is probably present. The nearby volcanic rocks are probably also altered in addition to being pyritized.

Production and reserves

Workings or exploration A grab sample contained 3,000 ppm copper but the molybdenum concentration in this sample was below detection (Patton and Csejtey, 1971, p. C8). Composite chip samples collected across the stock contained 700 ppm copper or less (Patton and Csejtey, 1971, p. C13). The only sulfide mineral identified in the volcanic rocks is pyrite but a grab sample of massive pyritized rock contained 1,500 ppm copper, 10 ppm silver, and 30 ppm molybdenum. Fourteen stream sediment samples collected over about 1.5 miles of the nearby headwater drainages (Patton and Csejtey, 1972) contained anomalous to highly anomalous concentrations of copper (to 1,500 ppm), molybdenum (to 70 ppm), and silver (to 1.5 ppm).
Indication of production None

References