Phonolite (Cripple Creek Diatreme, Oligocene; Beacon Hill, Colorado, USA) 1 : 無料・フリー素材/写真
Phonolite (Cripple Creek Diatreme, Oligocene; Beacon Hill, Colorado, USA) 1 / 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 | Phonolite from the Tertiary of Colorado, USA. (public display, Geology Department, Wittenberg University, Springfield, Ohio, USA)Central Colorado's Cripple Creek Mining District is famous for having 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 the scarce igneous rock phonolite, an alkaline, intermediate, extrusive igneous rock (see above sample). Cripple Creek gold can be found in its native state (Au), but it typically occurs in the form of gold telluride minerals (for example, sylvanite - (Au,Ag)2Te4, calaverite - AuTe2, 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 tetrahedrite - (Cu,Fe,Ag,Zn)12Sb4S13.Locality: unrecorded/undisclosed site at Beacon Hill, next to the town of Cripple Creek, southern Teller County, central Colorado, USA |
| 撮影日 | 2018-03-24 12:57:55 |
| 撮影者 | James St. John |
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