Chevron folds in gneiss (Precambrian; Medicine Bow Mountains, Wyoming, USA) 1 : 無料・フリー素材/写真
Chevron folds in gneiss (Precambrian; Medicine Bow Mountains, Wyoming, 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 | Gneiss from the Precambrian of Wyoming, USA. (public display, Nebraska State Museum of Natural History, Lincoln, Nebraska, USA)Gneiss is a high-grade, foliated metamorphic rock. It forms principally by metamorphism of schist, granite, or granite-like rocks. The foliation in gneiss is obvious and consists of alternating bands of light and dark minerals. The light-colored component is usually quartz (SiO2).The foliation of this gneiss sample has V-shaped folds (chevron folds).----------------------------------------From exhibit signage:Stress and strain caused this rock in the Medicine Bow Mountains of Wyoming to crumple into V-shaped folds. Layers of compressed clay, silt, and mud (shale) buckle and fold when subjected to high temperatures and pressures deep inside the Earth. Those changes produced the metamorphic rock you see here.----------------------------------------Locality: unrecorded/undisclosed site in the Medicine Bow Mountains of southeastern Wyoming, USA |
| 撮影日 | 2011-07-17 11:41:48 |
| 撮影者 | James St. John |
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