Occurrence, Active

Alternative names

Costello Creek

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals arsenopyrite; chalcopyrite; galena; pyrite; pyrrhotite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale B-5
Latitude 63.26
Longitude -149.47
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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).

Geologic setting

Geologic description

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).
Geologic map unit (-149.47228752178, 63.259529411809)
Mineral deposit model Polymetallic vein and Au-Ag breccia pipe or Cu-Au porphyry (Cox and Singer, 1986; models 22c, 20c)
Mineral deposit model number 22c, 20c
Age of mineralization Late Cretaceous (70-65 Ma) or younger.
Alteration of deposit Alteration consists of widespread propylitic alteration and silicification. Local zones of potassic alteration (secondary biotite) have been reported.

Production and reserves

Workings or exploration
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).
Indication of production None


MRDS Number A011306


Salisbury and Dietz, Inc., 1984, 1983 mineral resource studies--Kantishna Hills and Dunkle Mine areas, Denali National Park and Preserve, Alaska: U.S. Bureau of Mines, Contract No. S0134031, 1,080 p.
Reporters N. Van Wyck (Stevens Exploration Management Corporation)
Last report date 4/7/2000