Crystal Cave (Kentucky)
| Mammoth Cave National Park | |
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IUCN category II (national park)
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The Rotunda Room at Mammoth Cave
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| Location | Edmonson, Hart, and Barren counties, Kentucky, U.S. |
| Nearest city | Brownsville |
| Coordinates | 37°11′N 86°6′W / 37.183°N 86.100°WCoordinates: 37°11′N 86°6′W / 37.183°N 86.100°W |
| Area | 52,830 acres (213.8 km2) |
| Established | July 1, 1941 |
| Visitors | 586,514 (in 2016) |
| Governing body | National Park Service |
| Website | Mammoth Cave National Park |
| Type | Natural |
| Criteria | vii, viii, x |
| Designated | 1981 (5th session) |
| Reference no. | 150 |
| State Party |
 United States
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| Region | Europe and North America |
Mammoth Cave National Park is a U.S. national park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the even-longer system under Flint Ridge to the north, the official name of the system has been the Mammoth-Flint Ridge Cave System. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.
The park's 52,830 acres (21,380 ha) are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered on the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. With 405 miles (652 km) of surveyed passageways Mammoth Cave is by far the world's longest known cave system, being nearly twice as long as the second-longest cave system, Mexico's Sac Actun underwater cave.
Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone, making the system remarkably stable. It is known to include more than 390 miles (630 km) of passageway; new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system.
The upper sandstone member is known as the Big Clifty Sandstone: thin, sparse layers of limestone interspersed within the sandstones give rise to an epikarstic zone, in which tiny conduits (cave passages too small to enter) are dissolved by the natural acidity of groundwater. The epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges. The resurgent water from these springs typically flows briefly on the surface before sinking underground again at elevation of the contact between the sandstone caprock and the underlying massive limestones. It is in these underlying massive limestone layers that the human-explorable caves of the region have naturally developed.
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Wikipedia