Mt. Fairplay; Fairplay Prospects, Fortymile District, Southeast Fairbanks Borough, Alaska, USA

Latitude & Longitude (WGS84):	63° 41' 23'' North , 142° 14' 23'' West
Latitude & Longitude (decimal):	63.6897222222, -142.239722222

Part of the Mt. Fairplay region lies on Doyon Ltd. selected lands. For more information, contact Doyon Ltd.
Location: The Fairplay prospects are in a large block of claims that cover about 20 square miles on Mount Fairplay. The center of most activity is in section 14, T. 22 N., R. 16 E., of the Copper River Meridian, and is location 5 of Singer and others (1976), and location 6 of Eberlein and others (1977). The Taylor Highway passes just to the west of Mt. Fairplay, and much of the claim block is easily accessible by this road. The location is accurate.
Geology: The Fairplay prospects consist of disseminated chalcopyrite, galena, molybdenite, pyrite, and sphalerite that occur in hydrothermally altered Tertiary hypabyssal syenite and associated felsic volcanic rocks (Singer and others, 1976). Syenite that intrudes the felsic volcanic rocks at Mt. Fairplay has a K/Ar age of 67 +/- 2 Ma and contains minor gold-bearing quartz veins (Kerin, 1976; Wilson and others, 1985; Newberry and others, 1996). The Fairplay prospect area was staked in the early 1970's, and there are other similar prospects nearby (Singer and others, 1976). The syenite complex at Mt. Fairplay is similar to others in the Carmacks metallogenic belt of the Mount Nansen-Cash area in the Yukon Territory (Indian and Northern Affairs Canada, 1987).
Workings: Surface exploration was conducted and silt and soil samples were taken by WGM Inc. in 1975-76. More recent activity is very probable.
Age: The syenite at Mt. Fairplay is about 70 Ma, based on K-Ar ages (Kerin, 1976). The felsic intrusive and extrusive rocks that host the syenite are Tertiary.
Alteration: Hydrothermal alteration (Singer and others, 1976).

Commodities (Major) - Cu; (Minor) - Au, Mo, Pb, Zn
Development Status: None
Deposit Model: Porphyry Cu-Mo deposit (Cox and Singer, 1986; model 21a)

Mineral List

6 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Neogene - Paleogene 2.588 - 66 Ma

Igneous: extrusive; Extrusive: undivided Age: Cenozoic (2.588 - 66 Ma) Description: Eastern Alaska, Yukon, Mackenzie region, Yukon-Tanana upland Comments: Orogen, magmatic arc/suite; Wilson & Hults, unpublished compilation, 2007-08 Lithology: Volcanic rocks; lava flows, pyroclastic debris Reference: J.C. Harrison, M.R. St-Onge, O.V. Petrov, S.I. Strelnikov, B.G. Lopatin, F.H. Wilson, S. Tella, D. Paul, T. Lynds, S.P. Shokalsky, C.K. Hults, S. Bergman, H.F. Jepsen, and A. Solli. Geological map of the Arctic. doi:10.4095/287868. Geological Survey of Canada Map 2159A. [2]

Late Cretaceous - Early Tertiary 66 Ma

Welded tuff and other felsic volcanic rocks Age: Paleocene (66 Ma) Description: Felsic volcanic rocks Lithology: Igneous Reference: Wilson, F.H., Hults, C.P., Mull, C.G, and Karl, S.M. (compilers). Geologic map of Alaska. doi: 10.3133/sim3340. U.S. Geological Survey Scientific Investigations Map 3340, pamphlet 196. [21]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

References