Roosevelt Creek; RO; Skroo Prospect, Koyukuk Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Roosevelt Creek; RO; Skroo Prospect	Prospect
Koyukuk Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Core samples from three drill holes from the Roosevelt Creek and/or RO prospects are stored at the Alaska Geologic Materials Center in Eagle River, Alaska.
Location: This prospect is located near Roosevelt Creek about two miles north of the Malamute Fork, Alatna River. A large claim group which extends about 10 miles east and west and 1 to 1.5 miles north and south, is shown by Dillon and others (1981, Plate 1 [AOF 133B]); it is presumed to correspond to this prospect. The location is accurate within 1 mile.
Geology: Sparse published information about the Roosevelt Creek prospect principally cites oral communications and reports of unpublished industry data. The most recent of the published reports (Nokleberg and others, 1996) describes the Roosevelt Creek prospect as massive and disseminated(?) sulfides in metavolcanics, pelitic schists and marbles of the Devonian and Mississippian, Ambler sequence. The sulfides are described as probably chalcopyrite, sphalerite, and galena. Dillon and others (1986) map the general area of the prospect as Devonian, metavolcanic rocks and Proterozoic(?) or lower Paleozoic schists of various types, along with local marble. Grybeck (1977) indicates that the geology and geochemistry of the area is similar to that to the west in the Ambler district. Kurtak and others (2002) examined the area during their study of the Koyukuk mining district. They report that the canyon on Roosevelt Creek exposes Devonian(?) muscovite schist, graphitic schist and metarhyolite in a sequence that trends generally east-west and dips 55o south. Drilling intersected narrow, discontinuous zones of massive to semi-massive pyrite, sphalerite, galena, and chalcopyrite mineralization in schist and metarhyolite. Several rock samples collected along Roosevelt Creek in the vicinity of the presumed location of the prospect are described in Dillon and others (1981 [AOF 133B]) as felsic schists or felsites, most of which contain 1-2% disseminated pyrite. One sample may contain as much as 3% disseminated chalcopyrite and another may contain galena. Chemical analysis of these samples showed that only one contained any base metals: it was weakly anomalous in Pb.
Workings: The prospect was explored by geophysics and drilling in 1978 (Kurtak and others, 2002). Grybeck (1977, loc. 1) reported 77 lode claims located in 1975, and Dillon and others (1981) show a large claim block extending at least 10 miles east-west and 1 to 1.5 miles north-south.

Commodities (Major) - Cu, Pb, Zn; (Minor) - Ag(?), Au(?)
Development Status: None
Deposit Model: Kuroko massive sulfide (Cox and Singer, 1986; model 28a)

Other Databases

Link to USGS - Alaska:	WI134

Other Regions, Features and Areas containing this locality

References