Unnamed (west-southwest of Chitsia Mountain)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Pb
Other commodities Ag; Au; Mo; Th; U; Zn
Ore minerals cerussite; galena; limonite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale D-1
Latitude 63.961
Longitude -150.3411
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 2300 feeton an unnamed ridge about 1.4 miles west-southwest of Chitsia Mountain. The location is accurate within 500 feet. It corresponds to number 33 of MacKevett and Holloway (1977), 74 of Bundtzen, Smith, and Tosdal (1976), 55 of Hawley and Associates (1978), and 83 of Bundtzen (1981), and is cited as an unnamed location by Cobb (1980 [OFR 80-363]).

Geologic setting

Geologic description

The country rock at this occurrence is metarhyolite porphyry of the Totatlanika Formation, a volcanic-rich unit of Late Devonian and Mississippian age (Bundtzen, 1981). The deposit is a mineralized quartz vein 1 to 3 feet thick that strikes N 20-40 W, and is almost vertical. The vein is oxidized to a lead- and silver-bearing limonitic boxwork (gossan) that contains cerussite and, probably, small amounts of remnant galena and sphalerite. Selected samples of the vein assayed 3.10-10.5 percent lead, 1.17-2.73 ounces of silver per ton, 0.24 percent zinc, 0.02 ounce of gold per ton, and up to 72 ppm molybdenum, 24 ppm uranium, and 15 ppm thorium (Bundtzen, 1981, table 10, number 83).
Although speculative, the trace element geochemistry of this vein is at least permissive of a syngenetic or diagenetic origin, related to Upper Devonian or Mississippian Totatlanika volcanism (Bundtzen, 1981). An Eocene age is also possible (see MM091).
Geologic map unit (-150.343430160417, 63.9605092737931)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Although speculative, the trace element geochemistry of this vein is at least permissive of a syngenetic or diagenetic origin, related to Upper Devonian or Mississippian Totatlanika volcanism (Bundtzen, 1981). An Eocene age is also possible (see MM091).
Alteration of deposit Oxidation of iron and lead minerals.

Production and reserves

Workings or exploration There are no workings.
Indication of production None

Additional comments

The occurrence is in Denali National Park and Preserve.

References