Ptarmigan I

Occurrences, Probably inactive

Alternative names

Ptarmigan II
R-2290

Commodities and mineralogy

Main commodities Cu; Zn
Other commodities Ag; Au; Pb; Mo; Sn

Geographic location

Quadrangle map, 1:250,000-scale NL
Quadrangle map, 1:63,360-scale B-3
Latitude 64.4
Longitude -157.2
Nearby scientific data Find additional scientific data near this location
Location and accuracy The geologically similar Ptarmigan I, Ptarmigan II, and R-2290 occurrences are in area east and south of Totson Mountain. The coordinates are for the Ptarmigan I occurrence, which is at the approximate center of the area. Ptarmigan I is approximately 2 miles east of the summit of Totson Mountain and 1 mile north of Hill 2591. Ptarmigan II is approximately 2 miles southeast of Ptarmigan I, and 1 mile east-northeast of hill 2613. R-2290 is approximately 2 1/2 miles southwest of Ptarmigan I, and 2 miles south of Totson Mountain. The location is accurate within 5 miles.

Geologic setting

Geologic description

Ptarmigan I, Ptarmigan II, and R-2290 are small, individual, gossan occurrences in about a 3-square-mile area. The country rocks in the area are Paleozoic to Proterozoic schist and quartzite (Patton and Moll-Stalcup, 2000). Ptarmigan I consists of scattered float of massive gossan and schist in rubble of quartz schist, dolomite, mica schist, and phyllite. Ten rock samples of the gossan material contained up to 290 ppm copper, 99 ppm lead, 1500 ppm zinc, 1.2 ppm silver, 25 ppb gold, 13 ppm molybdenum, and 10 ppm tin. Three soil lines in the vicinity of Ptarmigan I indicate weakly anomalous copper and gold values but no obvious trend (Flanigan, 1998).
Ptarmigan II is a shear zone with gossan breccia that cuts a schistose micaceous quartzite. Twelve rock samples contain up to 595 ppm copper; soil samples are weakly anomalous in copper, silver, and gold (Flanigan, 1998).
R-2290 is a limonitic ankerite-quartz boulder on a game trail near a stream. Although the source of the boulder was not found, gossan fault breccia occurs uphill, in quartz schist rubble. Several rock samples contain up to 500 ppm copper and 494 ppm zinc (Flanigan, 1998).
Also see NL008, 009, and 011.
Geologic map unit (-157.202458405212, 64.3993600488692)
Mineral deposit model Plutonic-related Cu-Zn?
Age of mineralization Based on similarities to the Paw Print occurrence (NL009) and proximity to the Round Top (NL011) intrusion, the age of the deposit may be the same as the age of Round Top intrusion, about 73 Ma (Flanigan, 1998).
Alteration of deposit Iron-oxide alteration (gossan).

Production and reserves

Workings or exploration These occurrences were discovered by Anaconda Minerals Company in 1980 (Flanigan, 1998).
Indication of production None

References

MRDS Number 10307888

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