Melanterite-rich mine effluent (Mollie Kathleen Gold Mine, Cripple Creek Mining District, Colorado, USA) 2 : 無料・フリー素材/写真
Melanterite-rich mine effluent (Mollie Kathleen Gold Mine, Cripple Creek Mining District, Colorado, USA) 2 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | The Cripple Creek Gold District of central Colorado is famous for its unusual gold and silver mineralization. Precious metal mineralization occurs in the Cripple Creek Diatreme, the root zone of a deeply eroded volcano dating to the Early Oligocene (32 Ma). The dominant lithology at Cripple Creek is phonolite, a scarce, alkaline, intermediate, extrusive igneous rock. Cripple Creek gold can be found in its native state (Au), but it typically occurs in the form of gold telluride minerals: for example, calaverite - AuTe2, sylvanite - (Au,Ag)2Te4, petzite - Ag3AuTe2, krennerite - (Au,Ag)Te2, and nagyagite - Pb5Au(Sb,Bi)Te2S6). Silver also occurs in some Cripple Creek minerals, including sylvanite, petzite, krennerite, hessite - Ag2Te, tennantite - (Cu,Ag,Fe,Zn)12As4S13, acanthite - Ag2S, and argentian tetrahedrite - (Cu,Fe,Ag,Zn)12Sb4S13.The greenish material seen in the photo is melanterite-rich mine effluent, which refers to crystals forming on the walls and ceiling of mines. This is on the ceiling of a deep subsurface gold mine in Colorado. Mine effluent is not technically composed of minerals, because it is not natural - mines and mine tunnels are manmade constructs. Melanterite is a greenish-colored hydrous iron sulfate, FeSO4·7H2O. It can be naturally-occurring if it forms on weathered, natural rock surfaces. Iron and sulfur are needed to make melanterite. In the case seen here, the host rocks for the gold-bearing veins are pyritic phonolites. Pyrite is iron sulfide (fool's gold), FeS2. Oxidation in the presence of water readily breaks down pyrite. The oxidation-hydration products include melanterite.Geologic unit: Cripple Creek Diatreme, Early Oligocene, ~32 MaLocality: ceiling of the 1000' Level of the Mollie Kathleen Gold Mine, east of the town of Cripple Creek, Cripple Creek Mining District, southern Teller County, central Colorado, USA (38° 45' 11.02" North latitude, 105° 09' 37.96" West longitude)------------------------------------------See info. at:en.wikipedia.org/wiki/Melanterite |
| 撮影日 | 2007-07-28 19:42:01 |
| 撮影者 | James St. John |
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