Quartzite (Archean; Hellroaring Plateau, Beartooth Mountains Montana, USA) : 無料・フリー素材/写真
Quartzite (Archean; Hellroaring Plateau, Beartooth Mountains Montana, USA) / 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 | Quartzite from the Precambrian of Montana, USA. (public display, Museum of the Rockies, Bozeman, Montana, USA)Quartzite is a crystalline-textured, quartzose rock. They form by intermediate- to high-grade metamorphism of quartzose sandstones or siltstones. The term "quartzite" has also been applied to very hard, very well-cemented quartzose sandstones that have not undergone metamorphism. Metamorphic quartzite is sometimes called "metaquartzite" to prevent confusion.The quartzite seen here is from Montana's Beartooth Mountains, where Archean-aged rocks are common - these are some of the oldest rocks on Earth.--------------------------------From exhibit signage:Look for the small, brownish red minerals in this quartzite. These zircons formed in this specimen 3.96 billion years ago, an indication that some of the oldest rock in North America can be found in the Beartooth Mountains.--------------------------------Locality: unrecorded/undisclosed site on the Hellroaring Plateau, Beartooth Mountains, southern Montana, USA |
| 撮影日 | 2008-09-01 10:59:15 |
| 撮影者 | James St. John |
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