Travertine dripstone (Luray Caverns, Luray, Virginia, USA) 8 : 無料・フリー素材/写真
Travertine dripstone (Luray Caverns, Luray, Virginia, USA) 8 / 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 | Travertine dripstone in a cave in Virginia, USA."Cave formations" in caves are technically called speleothem. Most speleothem is composed of travertine, a crystalline-textured chemical sedimentary rock composed of calcite (CaCO3). Travertine forms in most caves and at some springs by precipitation of crystals from water. Travertine speleothem occurs in a wide variety of forms. The most common variety of travertine speleothem is dripstone, which forms by the action of dripping water. The second-most common type of travertine speleothem is flowstone, which forms by precipitation of crystals from relatively thin films of flowing water. Flowstone typically has the appearance of a frozen waterfalls.Downward-tapering dripstone structures attached to cave ceilings or upper walls are called stalactites. The equivalent structures on the floor are called stalagmites. When fused together, they form columns.Pure travertine is white. The colors seen in most of the travertine shown above are from iron oxides.Luray Caverns is developed in structurally-tilted dolostones of the Beekmantown Dolomite (Lower Ordovician).Locality: Luray Caverns, Luray, central Page County, northern Virginia, USA |
| 撮影日 | 2016-05-12 15:14:55 |
| 撮影者 | James St. John |
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