Republican Prospect, Juneau Mining District, Juneau, Alaska, USAi
Regional Level Types | |
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Republican Prospect | Prospect |
Juneau Mining District | Mining District |
Juneau | City Borough |
Alaska | State |
USA | Country |
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Latitude & Longitude (WGS84):
58° 18' 59'' North , 134° 20' 38'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
Place | Population | Distance |
---|---|---|
Juneau | 32,756 (2017) | 4.7km |
Mindat Locality ID:
199662
Long-form identifier:
mindat:1:2:199662:6
GUID (UUID V4):
1af4357a-83d6-4e47-8d77-014e6dfdf921
Location: The Republican prospect is at an elevation of approximately 1,300 feet on the south side of Granite Creek. It is 2.25 miles east of Mt. Juneau and 1/8 mile east of junction of Granite Creek with Gold Creek in the SE1/4NE1/4 section 18, T. 41 S., R. 68 E. of the Copper River Meridian. The location is accurate.
Geology: The Republican prospect was discovered prior to 1916 and was developed by 4 adits. This area was explored extensively by Echo Bay Mines Ltd. from the mid-1980's through the 1990's. The prospect consists of carbonate-altered metagabbro that contains up to 2 percent disseminated pyrite. U.S. Bureau of Mines samples contain up to 0.2 ppm gold (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 zone 160 km long by 5 to 8 km wide 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 deposit at the Republican prospect was discovered prior to 1916 and was developed by 4 adits.
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: Metagabbro hostrock is altered to carbonate minerals.
Commodities (Major) - Au
Development Status: None
Deposit Model: Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
1 valid mineral.
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 2 - Sulphides and Sulfosalts | |||
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ⓘ | Pyrite | 2.EB.05a | FeS2 |
Other Databases
Link to USGS - Alaska: | JU152 |
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