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Abîme
In geography, an abîme is a vertical shaft in karst terrain that may be very deep and usually opens into a network of subterranean passages.Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 11. . The term is borrowed from French, where it means abyss or chasm. Definition Formation Abîmes are a structure which form late in the life of a limestone cave. They can be 1–10 metres in diameter and up to 50 metres in height vertically. The walls have grooves that serve as a contrast to the smooth nature of the rest of the cave. They are known to lie under heads of stream valleys, sinkholes, or along non-carbonated rocks. Water will occasionally fall down the shaft, creating subterranean waterfalls. Only a small portion of the abîme connects to the rest of the cavern. They can extend to the present water table, while the rest of the cavern lies above it. Other names Abîme are also known as pit caves in the United States and pot caves in England. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst Formations
Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering-resistant rocks such as quartzite given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. In regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's Oil and gas reserves and resource quantification, hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography
Geography (from Ancient Greek ; combining 'Earth' and 'write', literally 'Earth writing') is the study of the lands, features, inhabitants, and phenomena of Earth. Geography is an all-encompassing discipline that seeks an understanding of Earth and world, its human and natural complexities—not merely where objects are, but also how they have changed and come to be. While geography is specific to Earth, many concepts can be applied more broadly to other Astronomical object, celestial bodies in the field of planetary science. Geography has been called "a bridge between natural science and social science disciplines." Origins of many of the concepts in geography can be traced to Greek Eratosthenes of Cyrene, who may have coined the term "geographia" (). The first recorded use of the word Geography (Ptolemy), γεωγραφία was as the title of a book by Greek scholar Claudius Ptolemy (100 – 170 AD). This work created the so-called "Ptolemaic tradition" of geography, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Language
French ( or ) is a Romance languages, Romance language of the Indo-European languages, Indo-European family. Like all other Romance languages, it descended from the Vulgar Latin of the Roman Empire. French evolved from Northern Old Gallo-Romance, a descendant of the Latin spoken in Northern Gaul. Its closest relatives are the other langues d'oïl—languages historically spoken in northern France and in southern Belgium, which French (Francien language, Francien) largely supplanted. It was also substratum (linguistics), influenced by native Celtic languages of Northern Roman Gaul and by the Germanic languages, Germanic Frankish language of the post-Roman Franks, Frankish invaders. As a result of French and Belgian colonialism from the 16th century onward, it was introduced to new territories in the Americas, Africa, and Asia, and numerous French-based creole languages, most notably Haitian Creole, were established. A French-speaking person or nation may be referred to as Fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone Cave
A solutional cave, solution cave, or karst cave is a cave usually formed in a soluble rock like limestone (Calcium carbonate, with chemical formula ''CaCO3''). It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum. Process Bedrock is dissolved by carbonic acid in rainwater, groundwater, or humic acids from decaying vegetation, that seeps through bedding planes, faults, joints, and the like. Over time, the surface terrain breaks up into clints separated by grikes and punctuated by sinkholes into which streams may disappear, crevices expand as the walls are dissolved to become caves or cave system. These may turn into large caverns or ''dolines'' when the roof collapses. The portions of a solutional cave that are below the water table or the local level of the groundwater are flooded. Limestone caves The largest and most abundant solutional caves are located in limestone. Limesto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinkhole
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 also known as 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. Most sinkholes are caused by Karst topography, karst processes – the chemical dissolution of carbonate rocks, collapse or suffosion processes. Sinkholes are usually circular and vary in size from tens to hundreds of Metre, meters both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Sinkholes may form gradually or suddenly, and are found worldwide. Formation Natural processes Sinkholes may capture surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit Cave
A pit cave, shaft cave or vertical cave—or often simply called a pit (in the US) and pothole or pot (in the UK); jama in Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric Alpine karst)—is a type of cave which contains one or more significant vertical shafts rather than being predominantly a conventional horizontal cave passage. Pits typically form in limestone as a result of long-term erosion by water. They can be open to the surface or found deep within horizontal caves. Among US cavers, a pit, usually referred to as a 'pitch' in UK English, is a vertical drop of any depth that cannot be negotiated safely without the use of ropes or ladders. Pit caving Techniques Exploration of pit caves ("vertical caving", also called "potholing" in the UK and "pit caving" in US English) requires the use of equipment such as nylon kernmantle rope or cable ladders. The specialized caving techniques of single rope technique (S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Hole
A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Blue holes typically contain tidally influenced water of fresh, marine, or mixed chemistry. They extend below sea level for most of their depth and may provide access to submerged cave passages. Well-known examples are the Blue Hole of Dahab in the Red Sea, Dragon Hole in the South China Sea and, in the Caribbean, the Great Blue Hole and Dean's Blue Hole. ''Blue holes'' are distinguished from ''cenotes'' in that the latter are inland voids usually containing fresh groundwater rather than seawater. Description Blue holes are roughly circular, steep-walled depressions, and so named for the dramatic contrast between the dark blue, deep waters of their depths and the lighter blue of the shallows around them. Their water circulation is poor, and they are commonly anoxic below a certain depth; this enviro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenote
A cenote ( or ; ) is a natural pit, or sinkhole, resulting when a collapse of limestone bedrock exposes groundwater. The term originated on the Yucatán Peninsula of Mexico, where the ancient Maya commonly used cenotes for water supplies, and occasionally for sacrificial offerings. The name derives from a word used by the lowland Yucatec Maya——to refer to any location with accessible groundwater. In Mexico the Yucatán Peninsula alone has an estimated 10,000 cenotes, water-filled sinkholes naturally formed by the collapse of limestone, and located across the peninsula. Some of these cenotes are at risk from the construction of the new tourist Maya Train. Cenotes are common geological forms in low-altitude regions, particularly on islands (such as Cefalonia, Greece), coastlines, and platforms with young post-Paleozoic limestone with little soil development. The term ''cenote'', originally applying only to the features in Yucatán, has since been applied by researchers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave Of Swallows
The Cave of Swallows, also called the Cave of the Swallows (), is an open-air pit cave in the municipality of Aquismón, San Luis Potosí, Mexico. The elliptical mouth, on a slope of karst, is wide and is undercut around all of its perimeter, widening to a room approximately wide. The floor of the cave is a freefall drop from the lowest side of the opening, with a drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest sheer drop in the world. History The cave has been known to the local Huastec people since ancient times. T. R. Evans, Charles Borland, Randy Sterns, and Sid West were first shown the cave on 27 December 1966. The first documented descent was on 4 April 1967. Geology The cave is formed in the El Abra and Tamabra formations, limestones of Middle Cretaceous age. The cave's speleogenesis is still not fully known but is a result of solutional enlargement along a vertical fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellhole (cave)
Hellhole is a large and deep pit cave in Germany Valley of eastern West Virginia. It is the seventh longest cave in the United States and is home to almost half of the world's population of Virginia big-eared bat, Virginia big-eared bats. At , Hellhole is the deepest of several caves in the Valley. Hellhole has had a long and storied association with the National Speleological Society dating back to the creation of that organization in the early 1940s. Many basic caving techniques (e.g., the single rope technique) were developed in Hellhole's entrance drop. Description The only known entrance to Hellhole is a funnel-shaped pit entrance on the lower slopes of North Fork Mountain. Descent by rope through this spectacular and storied entrance shaft gives access to a vast chamber. From the time exploration began there in the 1940s, cavers have documented over of mapped passage in the Hellhole system. "Little Hellhole" is a well known pit deeper in the cave. Hellhole's passages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vrtiglavica
Vrtiglavica, also Vrtoglavica (both from Slovene ''vrtoglavica'' 'vertigo'), is a karst shaft on the Kanin Plateau, part of the Kanin Mountains, Western Julian Alps, on the Slovene side of the border between Slovenia and Italy. It has the deepest known pitch in the world, at . The cave formed in a glaciokarst landscape; that is, a karst landscape that was subjected to Pleistocene glacial activity. Plunging straight through the high-karst roof of the Kanin Plateau at 1,900 m above sea-level, Vrtiglavica is no labyrinth but a single, near-cylindrical shaft that falls the cave's entire surveyed depth of 643 m. Glacial scouring during the Pleistocene stripped away the plateau's soil cover and enlarged pre-existing fissures, allowing melt-water to dissolve the crystalline Dachstein limestone along a tight joint bundle and sculpt the current glaciokarst pipe. Because the lip of the entrance opens directly onto bare karst pavement, rain and seasonal snowmelt drop unh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
