Vertical shaft (Mammoth Dome, Mammoth Cave, Kentucky, USA) 2 : 無料・フリー素材/写真
Vertical shaft (Mammoth Dome, Mammoth Cave, Kentucky, USA) 2 / 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 | (from an old postcard; original photo by Ellis-Sawyer)-----------------------------Western Kentucky's Mammoth Cave is the longest cave system on Earth, with 426 miles known and mapped as of fall 2022. The name does not refer to the early discovery of fossil mastodon or mammoth bones here. Rather, the name refers to the immense size of many rooms and passages.The system has a variety of cave passages: tubular passages, canyon passages, vertical shafts (domepits), keyhole passages, and giant canyon passages.Mammoth Dome is a large, complexly-shaped domepit that can be viewed during the 2 hour, 2 mile long Historic Tour. Domepits are large, silo-shaped, dissolutional features in caves. They form in the vadose zone (above the water table) as downward-moving groundwater dissolves limestone. Mammoth Dome corresponds to a surface sinkhole (Mammoth Dome Sink) that can be observed along a hiking trail that originates near the park's visitor center.One measurement puts Mammoth Dome at 150 feet tall. Park signage asserts that it is 192 feet tall.Flutes are common on the walls of vertical shafts. They are vertically-oriented dissolutional grooves formed as water moves downward.The rocks here are part of the lower Ste. Genevieve Limestone (upper Middle Mississippian). |
| 撮影日 | 2015-07-31 11:50:30 |
| 撮影者 | James St. John |
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