Unnamed (headwaters of theYuki River)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Cu; Zn
Other commodities Ag; Mo

Geographic location

Quadrangle map, 1:250,000-scale NL
Quadrangle map, 1:63,360-scale A-3
Latitude 64.22
Longitude -157.37
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence, locally called the Yuki River gossan, is near the headwaters of the Yuki River, in the southern Kaiyuh Mountains. For this record, the site is plotted at an elevation of about 800 feet, in the NW1/4 sec. 6, T. 15 S. R. 8 E., Kateel River Meridian. river. The location is accurate within 2 miles.

Geologic setting

Geologic description

This occurrence is a conspicuous ferricrete deposit 700 meters long and 2 to 5 meters thick along the Yuki River (Flanigan, 1998). The gossan is composed of rounded cobbles and pebbles of quartz-graphite schist, chlorite schist, quartzite, and greenstone in a limonite and manganese oxide matrix. The ferricrete rests unconformably on moderately to steeply dipping muscovite-quartz schist. Twenty-five rock samples contain values up to 180 ppm copper, 208 ppm zinc, 0.9 ppm silver, and 20 ppm molybdenum (Flanigan, 1998).
See also NL002, 008, 009, and 011.
Geologic map unit (-157.372449341753, 64.2193545507665)
Mineral deposit model Plutonic-related Cu-Zn
Age of mineralization Flanigan (1998) suggests that the molybdenum content of this occurrence may link it to the Round Top quartz monzonite intrusive complex (NL011), which has been dated at about 75 Ma.
Alteration of deposit Conspicuous iron-oxide alteration.

Production and reserves

Workings or exploration This occurrence was discovered by Anaconda Minerals Company in 1980 (Flanigan, 1998).
Indication of production None


MRDS Number 10307891


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