Coralloids (Martel Avenue, Mammoth Cave, Kentucky, USA) : 無料・フリー素材/写真
Coralloids (Martel Avenue, Mammoth Cave, Kentucky, 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 | Speleothem (= "cave formations") refers to all secondary mineral deposits in caves. Most speleothem is composed of calcium carbonate (CaCO3 - usually in the form of calcite, but sometimes aragonite). Calcareous speleothem is referred to using the rock name "travertine", a crystalline-textured, chemical sedimentary rock formed by precipitation from water.Coralloids are pustulose to nodulose, small to moderately large speleothem. They are also known as knobstone and cave popcorn. These examples are on a limestone wall along Martel Avenue in western Kentucky's Mammoth Cave, the longest cave on Earth. The system has 412 mapped miles, as of fall 2017.Click on the photo to zoom in and look around. The coralloids are in the upper half of the picture. The dimpled features in the lower half of the photo are scallops, which are asymmetrical, ridge-like, dissolutional features formed by flowing water. They somewhat resemble asymmetrical ripple marks, in that they form in a one-directional current, and the short side of each scallop represents the downstream direction. |
| 撮影日 | 2011-06-14 17:59:35 |
| 撮影者 | James St. John |
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