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Jewel Cave National Monument
Jewel Cave National Monument contains Jewel Cave, currently the fifth longest cave in the world and second longest cave in the United States, with of mapped passageways as of May 2024. It is located approximately west of the town of Custer in Black Hills of South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux .... It became a U.S. National Monument, national monument in 1908. History Frank and Albert Michaud, two local prospectors, discovered the cave in 1900, when they felt cold air blowing out of a small hole in a canyon. It is unknown whether any previous inhabitants of the area were aware of the natural cave opening, which was not large enough for a person to enter.Jewel Cave brochure; National Park Service; GPO, WDC After enlarging the cave entrance with dynamite, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Custer County, South Dakota
Custer County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 8,318. Its county seat is Custer. The county was created in 1875, and was organized in 1877. It was named after General George Armstrong Custer. Custer County is home to two of the three longest caves in the United States: Jewel Cave National Monument and Wind Cave National Park. Geography Custer County lies on the west line of South Dakota. Its west boundary line abuts the east boundary line of the state of Wyoming. The Cheyenne River flows northeastward along the upper portion of the county's east boundary. Battle Creek flows southeastward in the upper eastern part of the county, discharging into Cheyenne River along the county's northeastern boundary line. Spring Creek flows northeastward through the upper eastern part of the county, discharging into the river just north of the county border. The county terrain is mountainous, especially its western portion. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammoth Cave
Mammoth Cave National Park is a List of national parks of the United States, national park of the United States in south-central Kentucky. It encompasses portions of Mammoth Cave, the List of longest caves, longest known cave system in the world. The park's are located primarily in Edmonson County, Kentucky, Edmonson County, with small areas extending eastward into Hart County, Kentucky, Hart and Barren County, Kentucky, Barren counties. The Green River (Kentucky), Green River runs through the park, with a tributary called the Nolin River feeding into the Green just inside the park. The cave system has formally been known as the Mammoth–Flint Ridge Cave System since 1972, when a connection was discovered between Mammoth Cave and the even longer system under Flint Ridge to the north. As of 2022, more than of passageways had been surveyed, over 1.5 times longer than the second-longest cave system, Mexico's Sistema Sac Actun, Sac Actun underwater cave. The park was established ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers (Lamination (geology), laminae) less than one centimeter in thickness. This property is called ''Fissility (geology), fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the narrower sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand, sandstone may be imparted any color by impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topography, topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the Southwestern United States, American Southwest. Rock formations composed of sandstone usually allow the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippian (geology)
The Mississippian ( ), also known as Lower Carboniferous or Early Carboniferous, is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly 358.9 to 323.2 million years ago. As with most other geochronologic units, the rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years. The Mississippian is so named because rocks with this age are exposed in the Mississippi Valley. The Mississippian was a period of marine transgression in the Northern Hemisphere: the sea level was so high that only the Fennoscandian Shield and the Laurentian Shield were dry land. The cratons were surrounded by extensive delta systems and lagoons, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas. In North America, where the interval consists primarily of marine limestones, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of South Florida
The University of South Florida (USF) is a Public university, public research university with its main campus located in Tampa, Florida, Tampa, Florida, United States, and other campuses in St. Petersburg, Florida, St. Petersburg and Sarasota, Florida, Sarasota. It is one of 12 members of the State University System of Florida. USF is home to 14 colleges, offering more than 240 undergraduate, graduate, specialist, and doctoral-level degree programs. USF is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – Very high research activity" and is accredited by the Commission on Colleges of the Southern Association of Colleges and Schools. USF is a member of the Association of American Universities, Association of American Universities (AAU) and is designated by the Florida Board of Governors as one of three Preeminent State Research Universities. Founded in 1956, USF is the fourth largest university in Florida by enrollment, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Journal Of Speleology
The ''International Journal of Speleology'' is since 1978 the official peer-reviewed scientific journal of the ''Union Internationale de Spéléologie''. Since 1981 it has been published by the Società Speleologica Italiana. The ''International Journal of Speleology'' is divided into four sections: Botany-Microbiology, Zoology, Geology-Geomorphology, and Abstract-News. History The first issue was edited by G. Claus (US), subsequently two other editors were added: R. Husson (France) and G Nicholas (USA). The first two volumes were published by the J. Kramer Verlag (Germany), followed by Swets & Zeitlinger N.V. (The Netherlands). In 1972 R. Husson became editor in chief and nine volumes were issued in the period 1964 to 1977 until the cost of printing requested a radical change. In 1978 the journal became the official journal of the Union Internationale de Spéléologie and it was published in Italy where the cost of printing was lower. In 1981 V. Sbordoni (Italy) became editor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Pressure
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inchesHg, or 14.696 psi.International Civil Aviation Organization. ''Manual of the ICAO Standard Atmosphere'', Doc 7488-CD, Third Edition, 1993. . The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm. In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. Because the atmosphere is thin relative to the Earth's radius—especially the dense atmospheric layer at low altitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breathing Cave
A breathing cave or barometric cave is a rare type of cave in which atmospheric pressure gradients between the inside and outside of a cave cause air to flow in to or out of the cave. The concept of air flowing through a cave is common, but in most caves this airflow is caused by a difference in temperature rather than air pressure; in barometric caves the thermal mechanism inside the cave is not great enough to cause such airflow. The speed of the airflow in barometric caves is directly correlated with the atmospheric pressure difference between the inside and outside of the cave. When the air pressure outside of the cave is higher than that inside the cave air blows into the cave and vice versa; if the air pressures are at equilibrium there is no airflow. In some breathing caves, the airflow can only be meaningfully measured near the entrance. This tends to be the case in caves which primarily feature large, wide passageways, notably Wind Cave National Park, Wind Cave in South D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shuanghedong Cave Network
Shuanghedong (), is the longest cave in China, in Asia, and the 3rd longest in the world as of May 2023. It is located near the town of Wenquan in Suiyang County, Zunyi, Guizhou Province. The cave contains numerous waterfalls, and at least three underground rivers, some of which contain cave shrimp, and fish weighing several pounds. Tadpoles, frogs, salamanders, insects, spiders, bats, leeches, blind fish, and mushrooms have also been found. Since 1987, at least 20 expeditions from France and Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ... have explored the cave. In May 2023 the network reaches 400 kilometers of development. See also * List of caves in China * List of longest caves References External linksImages Caves of Guizhou Gypsum caves Karst formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundary, maritime boundaries with the Pacific Ocean to the west, the Caribbean Sea to the southeast, and the Gulf of Mexico to the east. Mexico covers 1,972,550 km2 (761,610 sq mi), and is the List of countries by area, thirteenth-largest country in the world by land area. With a population exceeding 130 million, Mexico is the List of countries by population, tenth-most populous country in the world and is home to the Hispanophone#Countries, largest number of native Spanish speakers. Mexico City is the capital and List of cities in Mexico, largest city, which ranks among the List of cities by population, most populous metropolitan areas in the world. Human presence in Mexico dates back to at least 8,000 BC. Mesoamerica, considered a cradle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
