Unnamed Prospect (ARDF - VA148; north of Thompson Pass), Prince William Sound Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Prospect (ARDF - VA148; north of Thompson Pass)	- not defined -
Prince William Sound Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is about 1.9 miles north of Thompson Pass and about one-quarter of a mile northwest of the trans-Alaska oil pipeline. It is at an elevation of about 2,500 feet in the SE1/4 section 22, T. 8 S., R. 3 W., of the Copper River Meridian. This prospect is probably located to within one-half mile. It is locality 91 of Winkler and others (1981 [OFR 80-892-B]).
Geology: Lode claims were staked and active from 1953 to 1955 on gold deposits at this locality (U.S. Bureau of Mines, 1980; Winkler and others, 1981 [OFR 80-892-B]). These deposits are probably gold-bearing quartz veins similar to others that are widespread in the southern Valdez quadrangle. Data summarized by Goldfarb and others (1997) show that gold-bearing quartz veins in the Valdez Group commonly contain pyrite, arsenopyrite, carbonate minerals, chlorite, and white mica and formed from water-rich fluids with 5 to 15 mole percent CO2 and significant amounts of CH4, N2, and H2S. The vein-forming fluid salinities were less than 8 percent, vein formation temperatures ranged from 225 to 375 degrees centigrade, and emplacement depths varied from 3 to 10 kilometers. The vein-forming fluids were produced by metamorphic devolatization reactions. Radiometric dating indicates that the veins formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Workings: Small-scale surface prospecting.
Age: Radiometric dating indicates that the gold-bearing quartz veins in the Valdez Group formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Alteration: Country rocks to gold-bearing quartz veins in Valdez Group metaflysch can be variably silicified, carbonitized, and sericitized (Goldfarb and others, 1997).

Commodities (Major) - Au
Development Status: Undetermined.
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Other Databases

Link to USGS - Alaska:	VA148

Other Regions, Features and Areas containing this locality

References