Mammoth Cave National Park is a national park in south-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The park's 52,830 acres (21,380 ha) are located primarily in Edmonson County, with small areas extending eastward into Hart and Barren counties. The Green River runs through the park, with a tributary called the Nolin River feeding into the Green just inside the park.
A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Harmony is a city in Fillmore County, Minnesota, United States. The population was 1,020 at the 2010 census. The town bills itself as the "Biggest Little Town in Southern Minnesota" and features the largest Amish community in the state.
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as vrtače and shakeholes, and to openings where surface water enters into underground passages known as ponor, swallow hole or swallet. A cenote is a type of sinkhole that exposes groundwater underneath. Sink and stream sink are more general terms for sites that drain surface water, possibly by infiltration into sediment or crumbled rock.
The Missoula floods were cataclysmic glacial lake outburst floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. These floods were the result of periodic sudden ruptures of the ice dam on the Clark Fork River that created Glacial Lake Missoula. After each ice dam rupture, the waters of the lake would rush down the Clark Fork and the Columbia River, flooding much of eastern Washington and the Willamette Valley in western Oregon. After the lake drained, the ice would reform, creating Glacial Lake Missoula again.
Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about 60 miles (100 km) southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee.
The Channeled Scablands are a relatively barren and soil-free region of interconnected relict and dry flood channels, coulees and cataracts eroded into Palouse loess and the typically flat-lying basalt flows that remain after cataclysmic floods within the southeastern part of Washington state. The Channeled Scablands were scoured by more than 40 cataclysmic floods during the Last Glacial Maximum and innumerable older cataclysmic floods over the last two million years. These floods were periodically unleashed whenever a large glacial lake broke through its ice dam and swept across eastern Washington and down the Columbia River Plateau during the Pleistocene epoch. The last of the cataclysmic floods occurred between 18,200 and 14,000 years ago.
At 150.4 miles (242.0 km), Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition.
J Harlen Bretz was an American geologist, best known for his research that led to the acceptance of the Missoula Floods and for his work on caves.
Greenleafton is an unincorporated community in York Township, Fillmore County, Minnesota, United States.
Joseph Thomas Pardee was a U.S. geologist who worked for the U.S. Geological Survey, and contributed to the understanding of the origin of the Channeled Scablands. He discovered the trail of evidence left by Glacial Lake Missoula, a lake created by an ice dam 23 miles (37 km) wide and 0.5 miles (0.8 km) high during the most recent ice age. He discovered that when the dam broke, the water flowed towards the scablands, supporting J Harlen Bretz's theory of the cataclysmic floods.
The Touchet Formation or Touchet beds consist of well-bedded, coarse to fine sand and silt which overlays local bedrock composed of Neogene basalt of the Columbia River Basalt Group in south-central Washington and north-central Oregon. The beds consist of more than 40 to 62 distinct rhythmites – horizontal layers of sediment, each clearly demarcated from the layer below. These Touchet beds are often covered by windblown loess which were deposited later; the number of layers varies with location. The beds vary in thickness from 330 ft (100 m) at lower elevations where a number of layers can be found to a few extremely thin layers at the maximum elevation where they are observed.
Drumheller Channels National Natural Landmark showcases the Drumheller Channels, which are the most significant example in the Columbia Plateau of basalt butte-and-basin Channeled Scablands. This National Natural Landmark is an extensively eroded landscape, located in south central Washington state characterized by hundreds of isolated, steep-sided hills (buttes) surrounded by a braided network of numerous channels, all but one of which are currently dry. It is a classic example of the tremendous erosive powers of extremely large floods such as those that reformed the Columbia Plateau volcanic terrain during the late Pleistocene glacial Missoula Floods.
Women in geology concerns the history and contributions of women to the field of geology. There has been a long history of women in the field, but they have tended to be under-represented. In the era before the eighteenth century, science and geological science had not been as formalized as they would become later. Hence early geologists tended to be informal observers and collectors, whether they were male or female. Notable examples of this period include Hildegard of Bingen who wrote works concerning stones and Barbara Uthmann who supervised her husband's mining operations after his death. Mrs. Uthmann was also a relative of Georg Agricola. In addition to these names varied aristocratic women had scientific collections of rocks or minerals.
The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain.
An underground lake or subterranean lake is a lake underneath the surface of the Earth. Most naturally occurring underground lakes are found in areas of karst topography, where limestone or other soluble rock has been weathered away, leaving a cave where water can flow and accumulate.
A subterranean waterfall or underground waterfall is a waterfall located underground, usually in a cave or mine. They are a common feature in cave systems where there are vertical or near vertical geological structures for the weathering process to exploit, and sufficient gradient between the sink and the rising. The highest known subterranean waterfall is in Vrtoglavica Cave in Slovenia, and is at least 400 metres (1,300 ft). A renowned example in the United States is Ruby Falls, 44 metres (144 ft) high, in Lookout Mountain Caverns, a show cave in Tennessee.
During the Vashon Glaciation a series of lakes formed along the southern margin of the Cordilleran Ice Cap. In the Puget Sound depression, a series of lakes developed, of which Lake Russell was the largest and the longest lasting. Early Lake Russell’s surface was at 160 ft (49 m) above sea level, draining across the divide at Shelton, Washington into early Glacial Lake Russell. When the ice margin receded northward, the lake expanded. When it reached the Clifton channel outlet, the water levels dropped to 120 ft (37 m) above sea level. The new longer and lower level lake is referred to as Lake Hood. The glacier continued to retreat until the northern outlet of the Hood Canal was reached as the water level equalized with Glacial Lake Russell becoming part of that body of water.
Devil's Icebox is a cave located in Rock Bridge Memorial State Park in Columbia, Missouri. It is said to be one of the longest caves in the state of Missouri and is one of the caves with the highest number of species in the state. It is currently closed to protect the endangered Indiana bat, and is the only known natural home of the species Kenkia glandulosa or pink planarian.
