Snoopy; Costello Creek Occurrence, Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Snoopy; Costello Creek Occurrence	Occurrence
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Location: The Snoopy occurrence, often linked to the nearby Nim claim block (HE074), covers a 0.25 by 0.75 mile area. The map site is at the center of the area, in sec. 21, T. 19 S., R. 10 W., of the Fairbanks Meridian. Useful published maps showing the general location of the Snoopy prospect are: Hawley and Clark (1974); Hawley and others (1978); Bundtzen (1983); and Salisbury and Dietz (1984).
Geology: Thick Quaternary glacial deposits cover much of the bedrock at the Snoopy prospect. The country rocks in the area are Upper Triassic to Upper Jurassic crystal tuff, argillite, chert, graywacke, and limestone. These strata are intruded by garnetiferous diorite porphyry, which in turn is cut by monzonite porphyry and quartz porphyry. The intrusive rocks are correlated with similar hypabyssal plutons at the Golden Zone mine (HE043), which have been dated as Late Cretaceous (Swainbank and others, 1977). The deposit is poorly exposed. It mat be a breccia pipe or a porphyry deposit that contains as much as 3% disseminated sulfides (Hawley and Clark, 1974). The sulfide minerals are arsenopyrite, chalcopyrite, galena, pyrite, pyrrhotite, and sphalerite. Selected samples contain 0.5 to 0.7 ppm gold, 200 to more than 10,000 ppm silver, and 150 to 1,000 ppm copper (Hawley and Clark, 1974). The Snoopy deposit probably is an extension of the deposit at the adjacent Nim prospect (HE074), where geophysical methods indicate 5 breccia-pipes in addition to disseminated porphyry-style mineralization. The same geophysical surveys suggest that the Snoopy area may contain 2 more pipes (Bundtzen, 1983, fig. 5).
Workings: Surface workings including trenching and drilling. Intensive exploration in the late 1970s included 18 shallow reverse-circulation drill holes in the Snoopy and Nim prospect areas. Geophysical surveys including IP and magnetics were conducted on the property (Bundtzen, 1983). Selected samples contain 0.5 to 0.7 ppm gold, 200 to more than 10,000 ppm silver, and 150 to 1,000 ppm copper (Hawley and Clark, 1974).
Age: Late Cretaceous (70-65 Ma) or younger.
Alteration: Alteration consists of widespread propylitic alteration and silicification. Local zones of potassic alteration (secondary biotite) have been reported.

Commodities (Major) - Ag, Au, Cu
Development Status: None
Deposit Model: Polymetallic vein and Au-Ag breccia pipe or Cu-Au porphyry (Cox and Singer, 198

Other Databases

Link to USGS - Alaska:	HE072

Other Regions, Features and Areas containing this locality

References