Unnamed Prospect (ARDF - JU023; Greek Boy upper pits), Juneau District, Juneau Borough, Alaska, USA
Location: This prospect consists of four open cuts that vary in elevation from 2,300 to 3,400 feet, about 5 miles north of the mouth of the Berners River where it empties into Berners Bay. It is 2 miles north-northeast of the Jualin mine (JU044), and 1.5 miles east of Lions Head Mountain, in the SW1/4 section 35, T. 34 S., R. 62 E. of the Copper River Meridian. The location marks the approximate center of several pits and is accurate. There are several adits 1 mile south-southeast of these workings which are the Greek Boy prospect (JU035). This prospect has sometimes been included with the Greek Boy prospect (Redman and others, 1989), but because of the great distance from the Greek Boy prospect, this prospect is listed as a separate prospect.
Geology: The prospect consists of four open cuts that follow a 4- to 10-foot-thick quartz vein in chlorite schist, 100 to 200 feet from diorite contact. The vein contains minor pyrite. U.S. Bureau of Mines samples from the pits contained up to 4.2 ppm gold, 3.5 ppm silver and 1,560 ppm copper (Redman and others, 1989). The prospect is within the Berners Bay district at the north end of the Juneau Gold Belt. The district is characterized by a series of structurally-controlled mesothermal, gold-bearing quartz veins. Most of the veins are in Late Cretaceous, Jualin Diorite, which intrudes Upper Triassic metabasalt (Miller and others, 1995). The age of mineralization in the Berners Bay area is about 55 Ma, the same as the other mesothermal gold vein deposits in the Juneau Gold Belt (Goldfarb and others, 1997).
Workings: The deposit has been explored by four open cuts.
Age: The age of mineralization in the Berners Bay district is about 55 Ma, the same as the other mesothermal gold-quartz-vein deposits in the Juneau Gold Belt (Goldfarb and others, 1997).
Commodities (Major) - Ag, Au, Cu
Development Status: No
Deposit Model: Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
ReferencesGoldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190. Miller, L.D., Goldfarb, R.J., Snee, L.W., Gent, C.A., and Kirkham, R.A., 1995, Structural geology, age, and mechanisms of gold vein formation at the Kensington and Jualin deposits, Berners Bay district, southeast Alaska: Economic Geology, v. 90, p. 343-368. Redman, E.C., Maas, K.M., Kurtak, J.M., and Miller, L.D., 1989, Bureau of Mines Mineral Investigations in the Juneau Mining District, Alaska, 1984-1988, Volume 2--Detailed mine, prospect, and mineral occurrence descriptions, Section D, Juneau Gold Belt Subarea: U.S. Bureau of Mines Special Publication, 424 p.
| Pyrite|| Quartz|
2 entries listed. 2 valid minerals.
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Locality Updated: Castro Laboreiro, Melgaço, Viana do Castelo District, PortugalFrom Rui Nunes, 12th Dec 2013 10:54:28