Roy Creek

Prospect, Inactive

Commodities and mineralogy

Main commodities U
Other commodities F; REE
Ore minerals allanite; bastnaesite; monazite; thorianite; thorite; uraninite; xenotime
Gangue minerals fluorite; hematite; topaz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale LG
Quadrangle map, 1:63,360-scale B-1
Latitude 65.4847
Longitude -147.0773
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located 42 miles northwest of Chena Hot Springs, 7.2 miles east-southeast from VABM 4772 'Cache Mountain', and 0.5 miles south of the center of section 26, T. 8 N., R 3 E., Fairbanks Meridian. It lies on the ridge between Roy and O'brian creeks. The location is accurate to within approximately 100 feet (Susan Karl, USGS, oral commun., 2014).

Geologic setting

Geologic description

This area contains significant uranium-rare earth mineralization. There are numerous uranium prospects, uraniferous springs and stream-sediments in the area (Barker and Clautice, 1977). Mt. Prindle pluton is a tourmaline- and topaz-bearing porphyritic biotite granite that crops out over a 50-square-km area. Country rock is quartzite and micaceous quartzite with subordinate quartz-mica schist, phyllitic schist and calcareous schist, thermally metamorphosed to upper hornblende facies near the pluton contact. The pluton is cut by three major NE-trending faults, and several quartz porphyry, aplite and pegmatite dikes.
Lithologies of the Roy Creek prospect consist of a Late Precambrian-Cambrian low grade metasedimentary asseblege intruded by a Cretaceous age alkaline complex (Burton, 1981). The intrusive complex consists of aegirine augite syenite and biotite augite porphric syenite.
Fissure veins containing allanite, bastnaesite, monazite, thorianite, thorite, uraninite, and xenotime occur in Cretaceous porphyritic biotite syenite and alkali granite (Burton, 1981). The deposit contains significant La, Cd, Nd, Pr, Yb, and fluorite. Hematitic alteration of wall rock and leaching of magnetite occurs in host rocks. Samples contain up to 0.1 percent U-238 and 15 percent rare-earth elements (Burton, 1981).
Geologic map unit (, )
Mineral deposit model U-REE deposit associated with a monzogranite.
Age of mineralization K-Ar dates of 85.4 - 86.7 Ma on augite syenite from the Roy Creek Pluton (Burton, 1981) when corrected with appropriate decay constants are 87.5+/-6.4 and 88.9+/-3.6 Ma.
Alteration of deposit There is hematitic alteration of wall rock and leaching of magnetite in host rocks (Burton, 1981).

Production and reserves

Workings or exploration Exploration in the Mt Prindle area has focused on radioactive mineral occurrences within the syenite and surrounding altered quartzites. Fissure veins contain anomalous U, Th, and REEs. Some exploration prospect pits and limited drilling was carried out at Roy Creek by MAPCO in the late 1970s but no further development has taken place. Claims were active from 1977 through at least 1981 (Menzie and others, 1983, p. 56).
Indication of production None

Additional comments

The 9/9/1998 version of this record combined the Roy Creek and Little Creek records and listed the coordinates for Little Champion Creek in the Circle quadrangle. The ARDF number for Little Champion Creek remains CI051.



Burton, P.J., 1981, Radioactive mineral occurrences, Mt. Prindle area, Yukon-Tanana Uplands: Fairbanks, University of Alaska, M.Sc. thesis, 72 p.
Reporters C.J. Freeman, J.R. Guidetti Schaefer, A.S. Clements (Avalon Development Corporation); V.C. ZInno (Alaska Earth Science, Inc.)
Last report date 3/15/2016