Unnamed (on Chitsia Mountain) (ARDF #MM004) Ba

Unnamed (on Chitsia Mountain)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Ba
Other commodities	Ag; Pb; Zn
Ore minerals	barite; galena; pyrite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale	MM
Quadrangle map, 1:63,360-scale	D-1
Latitude	63.9643
Longitude	-150.3046
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This 300-foot-long mineral occurrence (Cobb, 1980 [OFR 80-363]) is on a ridge crest about 2500 feet west-southwest of the top of Chitisia Mountain. The location is at the approximate midpoint of the occurrence and is accurate within 250 feet. The occurrence correponds to number 77 of Bundtzen, Smith, and Tosdal (1976), 58 of Hawley and Associates (1978), and 84 of Bundtzen (1981).

Geologic setting

Geologic description This occurrence is a stratiform deposit in schistose metarhyolite porphyry in the Upper Devonian to Mississippian Totatlanika Formation (Bundtzen, 1981, p. 82). The outcrop of the deposit is about 300 feet long and about 10 feet wide; it strikes ENE and dips about 30 NW (Hawley and Associates, 1978; fig. 4.1-A(3)). The deposit consists of barite-rich layers 1 to 6 inches thick in silicified(?) schist containing pyrite, galena, and sphalerite. Selected barite-rich samples contain 36-52 percent barium. Pyrite is fairly abundant; galena and sphalerite less so. Some grab samples assayed up to 3.1 percent lead and 0.8 ounce of silver per ton, but most contained 1 percent or less each of lead and zinc (Buntzen, Smith, and Tosdal (1976); Hawley and Associates, 1978; Bundtzen, 1981). The deposit is probably volcanogenic in origin, and formed in Late Devonian or Mississippian time.
Geologic map unit	(-150.306930562623, 63.963810466265)
Mineral deposit model	Distal, barite-rich, kuroko massive sulfide deposit (Cox and Singer, 1986; model 28a).
Mineral deposit model number	28a
Age of mineralization	The deposit is probably Late Devonian or Mississippian, the depositional age of the Totatlanika metarhyolite hostrock (Bundtzen, 1981).
Alteration of deposit	Silicification of Totatlanika schistose metarhyolite.

Production and reserves

Workings or exploration	The deposit was discovered during reconnaissance geologic mapping of the Kantishna district (Bundtzen, Smith, and Tosdal, 1976). There are no significant workings.
Indication of production	None
Additional comments The occurrence exemplifies stratiform, volcanogenic deposits in metarhyolite schist of the Upper Devonian to Mississippian Totatlanika Formation. It is in Denali National Park and Preserve.

References

MRDS Number	A011207
References Bundtzen, T. K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p. Bundtzen, T.K., Smith, T.E., and Tosdal, R.M., 1976, Progress report--Geology and mineral deposits of the Kantishna Hills: Alaska Division of Geological and Geophysical Surveys Open-File Report AOF-98, 80 p., 2 sheets, scale 1:63,360. Cobb, E.H., 1980, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount McKinley quadrangle, Alaska: U. S. Geological Survey Open-File Report 80-363, 150 p. Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, 379 p. Hawley, C. C. and Associates, Inc, 1978, Mineral appraisal of lands adjacent to Mt. McKinley National Park, Alaska: U. S. Bureau of Mines Open-File Report 24-78, 275 p. (paged by sections).
Reporters	C.C. Hawley
Last report date	5/7/2001