Townsend and Holland Prospect, Prince William Sound Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Townsend and Holland Prospect	Prospect
Prince William Sound Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is immediately below the Richardson Highway, about one-half mile west of mile 40. It is at benchmark Elbow (elevation of 1,656 feet) in the NW1/4 section 4, T. 8 S., R.1 W., of the Copper River Meridian. It is locality 42 of Cobb and Matson (1972) and locality 34 of Winkler and others (1981 [OFR 80-892-B]).
Geology: Gold-bearing quartz veins from 3 to 5 feet thick cut metaflysch of the Valdez Group at this prospect (Moffit, 1935). One vein strikes N 40 E and was followed in an adit for 300 feet. Open cuts and a 150-foot long adit were also used to explore the veins. These veins are probably 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: One vein strikes N 40 E and was followed in an adit for 300 feet. Open cuts and a150-foot long adit were also used to explore the veins (Moffit, 1935).
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: None
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Other Databases

Link to USGS - Alaska:	VA152

Other Regions, Features and Areas containing this locality

References