SUPPORT US. Covid-19 has significantly affected our fundraising. Please help!
登录注册
主页关于 MindatMindat手册Mindat的历史版权Who We Are联系我们于 Mindat.org刊登广告
捐赠给 MindatCorporate Sponsorship赞助板页已赞助的板页在 Mindat刊登 广告的广告商于 Mindat.org刊登广告
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe Elements书籍及杂志
搜索矿物的性质搜索矿物的化学Advanced Locality Search随意显示任何一 种矿物Random Locality使用minID搜索邻近产地Search Articles搜索词汇表更多搜索选项
搜索:
矿物名称:
地区产地名称:
关键字:
 
Mindat手册添加新照片Rate Photos产区编辑报告Coordinate Completion Report添加词汇表项目
Mining Companies统计会员列表Mineral Museums矿物展及活动The Mindat目录表设备设置The Mineral Quiz
照片搜索Photo GalleriesSearch by Color今天最新的照片昨天最新的照片用户照片相集过去每日精选照片相集Mineral Photography

Reagan Prospect, Juneau District, Juneau Borough, Alaska, USA

This page is currently not sponsored. Click here to sponsor this page.
 
 
Location: The Reagan prospect is at an elevation of approximately 1,100 feet,on the north side of Sheep Creek. It is 3/4 mile east-southeast of Portal Camp and 1.5 miles southeast of Sheep Mountain, in the NW1/4NW1/4 section 34, T. 41 S., R. 68 E. of the Copper River Meridian. The location is accurate.
Geology: The Reagan prospect was discovered in 1894 and has a 250-foot adit, 3 additional adits, a 42-foot winze, and a 40-foot shaft. Echo Bay Mines Ltd. explored the property in 1988. The deposit consists of 2 quartz veins in a shear zone along the contact between black phyllite and green phyllite. The veins dip southwest and are 1 to 3 feet thick. They contain arsenopyrite, chalcopyrite, electrum, galena, native silver, pyrite, sphalerite, and tetrahedrite. U.S. Bureau of Mines samples contained up to 52.2 ppm gold, 4,612.0 ppm silver, 1.71 percent zinc, and 0.97 percent lead. The U.S. Bureau of Mines has estimated a resource of 82,000 tons of ore of uncertain grade (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 Reagan prospect was discovered in 1894 and has a 250-foot adit, 3 additional adits, a 42-foot winze, and a 40-foot shaft. Echo Bay Mines Ltd. explored the property in 1988.
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).
Reserves: The U.S. Bureau of Mines has estimated a resource of 82,000 tons of material with an uncertain grade.

Commodities (Major) - Ag, Au, Cu, Pb, Zn
Development Status: No
Deposit Model: Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)

Mineral List



9 entries listed. 8 valid minerals.

The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

Gehrels, G.E., McClelland, W.C., Samson, S.D., and Patchett, P.J., 1991, U-Pb geochronology of detrital zircons from a continental margin assemblage in the northern Coast Mountains, southeastern Alaska: Canadian Journal of Earth Sciences, v. 28, no. 8, p.1285-1300. 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. Miller, L.D., Goldfarb, R.J., Gehrels, G,E., and Snee, L.W., 1994, Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska: Geology, v. 22, p. 203-206 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.

 
矿物 and/or 产地  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo
版权所有© mindat.org1993年至2021年,除了规定的地方。 Mindat.org全赖于全球数千个以上成员和支持者们的参与。
隐私政策 - 条款和条款细则 - 联络我们 - Report a bug/vulnerability Current server date and time: 2021.1.23 11:45:00 Page generated: 2015.1.17 06:25:55
Go to top of page