Unnamed Occurrence (ARDF - GO001; southwest of Sunshine Valley), Bristol Bay Region District, Dillingham Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - GO001; southwest of Sunshine Valley)	- not defined -
Bristol Bay Region District	- not defined -
Dillingham Census Area	Census Area
Alaska	State
USA	Country

This occurrence is within Wood-Tikchik State Park.
Location: This occurrence is on the ridge southwest of lower Sunshine Valley, near the north end of Lake Aleknagik. It is approximately located, perhaps within a mile. For this record, the map site is at an elevation of 1,000 feet at the head of an unnamed creek, just south of the center of section 25, T 8 S, R 58 W, of the Seward Meridian.
Geology: The ridge in the area of this occurrence is underlain by two small granitic stocks that sharply crosscut and thermally metamorphose Mesozoic sedimentary country rocks; other plutons may be present in the subsurface of the area (Mertie, 1938; Kilburn and others, 1993). A general area of mineralization and its relation to intrusive rocks on the ridge southwest of Sunshine Valley was originally reported by Mertie (1938, p. 88). This occurrence is in the contact zone of the easternmost of the two exposed plutons. Silicified and oxidized samples of argillite contained anomalous concentrations of Ag, As and Cu (Gray and others, 1992; Kilburn and others, 1993). The contact zone generally is iron-stained and silicified. Weakly mineralized hornfels contains some disseminated pyrite and small quartz-pyrite veinlets. Stream sediment and heavy mineral concentrate in the area contain anomalous concentrations of As, Au, Ba, Bi, Hg, Mo, Pb, Sn, W, and Zn, especially in streams headwatered near the granitic plutons (Cieutat and others, 1988).
Workings: Surface reconnaissance geochemical sampling has been completed in the area (Kilburn and others, 1993).
Age: Late Cretaceous or Early Tertiary. Mineralization is probably related to the granitic plutons in the area, which are part of a regionally extensive Upper Cretaceous and Lower Tertiary plutonic suite. K/Ar ages for samples collected from the western stock on this ridge are 69.5 +/-2.1 Ma on biotite and 63.4 +/- 1.9 Ma on hornblende (Hoare and Coonrad, 1978).
Alteration: Silicification and oxidation.

Commodities (Major) - Ag, Cu
Development Status: None
Deposit Model: Polymetallic veins (Cox and Singer, 1986; model 22c)

Other Databases

Link to USGS - Alaska:	GO001

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References