Large & small scallops (Rose's Pass, Mammoth Cave, Kentucky, USA) 16 : 無料・フリー素材/写真
Large & small scallops (Rose's Pass, Mammoth Cave, Kentucky, USA) 16 / 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 | Scallops developed on Mississippian limestone in a Kentucky cave, USA.The wavy features shown here are scallops - 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.These examples are on a limestone wall in Rose's Pass in western Kentucky's Mammoth Cave, the longest cave on Earth. The system has 412 mapped miles, as of fall 2017.Larger, longer scallops formed in slower-moving water. Smaller, shorter scallops formed in rapidly-moving water. Notice that two scales of scallops are present here - larger ones in the lower part of the picture and smaller ones above. Studies have shown that the larger scallops in Rose's Pass indicate a slower, northward flow. Most subterranean river flow in the Mammoth Cave system was to the north and northwest. The smaller scallops indicate more rapid flow to the south. The large scallops represent "normal" flow through Rose's Pass, while the smaller scallops were probably developed during flood stages - floodwaters backed up and headed southward.Stratigraphy: Ste. Genevieve Limestone, upper Middle MississippianLocality: Rose's Pass, between Boone Avenue and Jeanne's Avenue, Mammoth Cave Ridge, Mammoth Cave National Park, western Kentucky, USA |
| 撮影日 | 2011-06-14 16:21:25 |
| 撮影者 | James St. John |
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