Location: This prospect is on the northwest valley wall of Gold Fork at an elevation of 1,400 feet. It is about 1 mile upstream from the mouth of Carlson Creek in the NW1/4NW1/4 section 11, T. 41 S., R. 68 E. of the Copper River Meridian. The location is accurate.
Geology: The Gold Fork deposit was discovered in 1911 and developed by a 10-foot adit and a 150-foot adit. The deposit was explored by Curator American in 1988 and drilled by Kennecott Exploration and Echo Bay Mines in the early 1990's. The prospect is currently (2001) being explored (Dale Henkins, oral commun., 2001). The Gold Fork deposit consists of at least four, fault-controlled quartz veins and quartz-breccia zones in biotite-hornblende gneiss and banded calc-schist. The veins can be traced along the north side of Gold Fork on the surface for nearly 1,000 feet and vertically for nearly 600 feet. Reconnaissance drilling by Kennecott suggests a total strike length of over 8,000 feet. The veins are slightly banded, with alternating layers of quartz and graphitic schist, and are locally brecciated. The banded veins dip north to northeast, and contain pyrite, stibnite, arsenopyrite, and galena. Four major veins up to 20 feet thick have been identified. Noteworthy intercepts from Kennecott core drilling in 1992 included 17 feet with 0.35 ounce of gold per ton and 39 feet with 0.22 ounce of gold per ton (Huber and Barnett, 1989; Dale Henkins, oral commun., 2001) Quartz vein stockworks and stringers also occur as well as intense silicification in the adjacent wallrock. The veins appear to have undergone brecciation and subsequent healing by quartz and minor pyrite. These veins are crosscut by multiple generations of quartz-pyrite veinlets with associated clay-ankerite wall rock alteration (Redman and others, 1989). This prospect is in the Juneau Gold Belt, which consists of more than 200 gold-quartz vein deposits that have produced nearly 7 million ounces of gold. These gold-bearing mesothermal quartz vein systems form a 160-km-long by 5- to 8-km-wide zone along the western margin of the Coast Mountains. The vein systems are in or near shear zones adjacent to west-verging, mid-Cretaceous thrust faults. The veins are hosted by diverse, variably metamorphosed, sedimentary, volcanic, and intrusive rocks. From the Coast Mountains batholith westward, the host rocks include mixed metasedimentary and metavolcanic sequences of Carboniferous and older, Permian and Triassic, and Jurassic-Cretaceous age. The sequences are juxtaposed along mid-Cretaceous thrust faults (Miller and others, 1994). The sequences are intruded by mid-Cretaceous to middle Eocene plutons, mainly diorite, tonalite, granodiorite, quartz monzonite, and granite. Sheetlike tonalite plutons emplaced just east of the Juneau Gold Belt and undeformed granite and granodiorite bodies that are emplaced farther to the east are between 55 and 48 Ma (Gehrels and others, 1991). The structural grain of the belt is defined by northwest-striking, moderately to steeply northeast-dipping, penetrative foliation that developed between Cretaceous and Eocene time (Miller and others, 1994). The majority of the veins in the Juneau Gold Belt strike northwest. Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994; Goldfarb and others, 1997).
Workings: The Gold Fork deposit was discovered in 1911 and developed by a 10-foot adit and a 150-foot adit. The prospect was explored by Curator American in 1988 and drilled by Kennecott Exploration and Echo Bay Mines in the early 1990's. The prospect is currently (2001) being explored.
Age: Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994; Goldfarb and others, 1997).
Alteration: Silicification and clay-ankerite wall rock alteration.

Commodities (Major) - Ag, Au; (Minor) - Pb, Sb, Zn
Development Status: None
Deposit Model: Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)

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Mineral List

6 valid minerals.