Location: This prospect is at an elevation of 350 feet, on the north wall of lower Johnson Creek. It is 1.5 miles northwest of Berners Bay and 1.5 mile southeast of the Jualin mine (JU044), in the NE1/4 section 23, T. 35 S., R. 62 E. of the Copper River Meridian. The location is accurate.
Geology: The rocks at the Mystery prospect are similar to those at the Fremming prospect (JU049). They consist of light green, chloritic phyllite and greenstone. Redman and others (1989), interpret the Mystery prospect as a stratabound, volcanogenic massive sulfide deposit. However, exploration by International Curator Resources Ltd., combined with observations of drill core from both the Jualin Mine (JU044) and the nearby Fremming prospect (JU049), indicate that the predominant host rock is probably Jualin Diorite (Barnett and others, 1988). This interpretation is supported by Kaplar (1988) who showed that the diorite loses textural and mineralogical identity as shearing becomes more intense. Rocks at or near the Mystery workings thus can be classified as greenstone and phyllite, but their protolith probably was Jualin Diorite (Kapler, 1988). Workings at the Mystery prospect include a water-filled shaft and several sloughed-in pits. The shaft is sunk on a 3-foot-thick layer of light green phyllite that contains 5-15% disseminated pyrite, and massive pyrite layers parallel to the foliation. The pyrite layers are up to 2 inches thick. Samples contain up to 1.4 ppm gold, 1.5 ppm silver, and 5,500 ppm copper (Redman and others, 1989). The Mystery prospect is in the Jualin mine area (JU044), currently (2001) controlled by Coeur Alaska. It 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.
Workings: Workings at the Mystery prospect include a water-filled shaft and several sloughed-in pits.

Commodities (Major) - Ag, Au, Cu
Development Status: None

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

ⓘ Copper

ⓘ Gold

ⓘ Silver

Mineral List

ⓘ Pyrite

1 valid mineral.

Detailed Mineral List:

ⓘ Pyrite

Formula: FeS₂

References:

(2008) Alaska Resource Data File (ARDF) Open-File Report 2008-1225. US Geological Survey

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘ	Pyrite	2.EB.05a	FeS₂

List of minerals for each chemical element

S	Sulfur
S	ⓘ Pyrite	FeS₂
Fe	Iron
Fe	ⓘ Pyrite	FeS₂

Other Databases

Link to USGS - Alaska:	JU052

Other Regions, Features and Areas containing this locality

North AmericaContinent

Coast MountainsMountain Range

North America PlateTectonic Plate

Taku DomainDomain
Yukon-TananaVolcanic Arc

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References

Barnett, J.C., Hayden, T.J., Bair, D.K., and Croff, T.C., 1988, 1987 summary report, Jualin gold project, Berners Bay District: Unpublished report for International Curator Resources, Ltd., 75 p. Goldfarb, 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. Kaplar, J., 1988, Jualin prospect analysis--Petrographic microprobe, SEM, and XES geochemical analysis of core: Unpublished report for International Curator Resources, Ltd., Denver, Colo., 18p. 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.

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Mystery Prospect, Juneau Mining District, Juneau, Alaska, USAiRegional Level TypesMystery ProspectProspect Juneau Mining DistrictMining District JuneauCity Borough AlaskaState USACountry function showexplain() { $("#locexplain").toggle(); if (typeof movemap === "function") movemap(); }