Io Prospect, Chandalar Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Io Prospect	Prospect
Chandalar Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

See also: Deimos (CH061), Ginger (CH060), Hurricane-Diane (CH062), Venus (CH065), Pilgrim (CH099), Mike (CH100), Vicki (CH097), Cindy (CH098), and Evelyn Lee (CH059).
Location: The Io prospect is at an elevation of about 4,800 feet just above the headwaters of Robert Creek about 4 1/2 miles south of the confluence of Quartz Creek and the North Fork Chandalar River (SE1/4 sec. 2, T. 34 N., R. 7 W., of the Fairbanks Meridian). The location is accurate within a 1-mile radius.
Geology: The Io prospect is one of a number of skarn deposits in the Chandalar area. Newberry and others (1986) classified this prospect as a Pb-Zn-Ag-Cu skarn and group it with a number of similar prospects that are northwest of and related to the Devonian(?)granitic plutons in the Horace Mountains. Many of these skarns exhibit both garnet and pyroxene prograde and epidote and actinolite retrograde mineral assemblages, and Newberry and others (1986) stated their characteristics place them in the category of continental-margin, porphyry-related copper skarns. They also suggest that the Pb-Zn-rich skarns represent distal concentrations surrounding the porphyry systems in the district. Newberry and others (1997) classify the Io prospect as a calcic Zn-Pb skarn and replacement body. A hand specimen of skarn from Io contains epidote, chlorite, actinolite, pyrite, galena, sphalerite, and magnetite (Newberry and others, 1986). Analysis of this specimen returned values of 12.6 percent Pb, 8.5 percent Zn, 0.04 percent Cu and 83 ppm Ag. In a listing posted on the Ventures Resource Corporation (currently exploring Doyon, Limited lands in the area under an agreement with Doyon, Limited) website (1998, URL http://www.venturesresource.com/) the Io prospect is classified as a Cu-Au prospect, although no supporting data are shown. The prospect is in an area underlain principally by Devonian Skajit Limestone and Hunt Fork Shale (DeYoung, 1978).
Age: Devonian(?) based on reported Early Devonian Pb/Pb zircon ages from the associated Baby Creek batholith and Horace Mountain plutons (Dillon and others, 1996).
Alteration: Calc-silicate.

Commodities (Major) - Ag, Cu, Pb, Zn; (Minor) - Au(?)
Development Status: None
Deposit Model: Zn-Pb skarn deposits (Cox and Singer, 1986; model 18c)

Other Databases

Link to USGS - Alaska:	CH102

Other Regions, Features and Areas containing this locality

References