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Kilbourne Hole
Kilbourne Hole is a maar volcanic crater, located west of the Franklin Mountains of El Paso, Texas, in the Potrillo volcanic field of Doña Ana County, New Mexico. Another maar, Hunt's Hole, lies just two miles south of Kilbourne Hole. Kilbourne Hole is notable for the large number of mantle xenoliths, solid fragments of mantle rock, that were carried to the surface by the eruption. Estimates of the age of the crater vary from about 24,000 to about 80,000 years. In 1975, Kilbourne Hole was designated as a National Natural Landmark by the National Park Service. It is now part of Organ Mountains–Desert Peaks National Monument. Geologic setting and formation Kilbourne Hole and Hunt's Hole are found in the central part of the Potrillo volcanic field, which also contains the Afton-Aden basalt flows. The area is part of the Rio Grande rift, where the Earth's crust is being stretched and thinned. The rift is characterized by deep sedimentary basins, recent faulting and volcanic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilbourne And Hunts Holes And White Sands
Kilbourne may refer to: Places United States * Kilbourne, Illinois * Kilbourne, Louisiana * Kilbourne, Ohio United Kingdom * Kilburn, Derbyshire, historically also spelled Kilbourne Other uses * Kilbourne (DJ) * Kilbourne (surname) Kilbourne is a surname. Notable people with the surname include: * Ashe Kilbourne, DJ * Amos Kilbourne, English footballer * Charles E. Kilbourne (1872–1963), United States Army general * Edward C. Kilbourne (1856–1959) * Edwin D. Kilbourne (19 ... * Kilbourne High School, high school in Columbus, Ohio {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain shape, and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropstones
Dropstones are isolated fragments of rock found within finer-grained water-deposited sedimentary rocks or pyroclastic beds. They range in size from small pebbles to boulders. The critical distinguishing feature is that there is evidence that they were not transported by normal water currents, but rather dropped in vertically through the air or water column. Such deposition can occur i.e. during a volcanic eruption. Background When deposited into fine layered mud, such evidence includes an impact depression beneath the dropstone, and indication that the mud has been squeezed up around the edges of the falling rock. Subsequent deposits of mud drape over the dropstone and its crater. Glacial dropstones, involving rocks falling out of icebergs, are one of the most common types of dropstone preserved in the geological record, particularly when deposited in low-energy deep sea or lake environments. Dropstones differ from erratics found in glacial till in that they are deposited in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropstone At Kilbourne Hole
Dropstones are isolated fragments of rock found within finer-grained water-deposited sedimentary rocks or pyroclastic beds. They range in size from small pebbles to boulders. The critical distinguishing feature is that there is evidence that they were not transported by normal water currents, but rather dropped in vertically through the air or water column. Such deposition can occur i.e. during a volcanic eruption. Background When deposited into fine layered mud, such evidence includes an impact depression beneath the dropstone, and indication that the mud has been squeezed up around the edges of the falling rock. Subsequent deposits of mud drape over the dropstone and its crater. Glacial dropstones, involving rocks falling out of icebergs, are one of the most common types of dropstone preserved in the geological record, particularly when deposited in low-energy deep sea or lake environments. Dropstones differ from erratics found in glacial till in that they are deposited in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically have a concave upwards form, where the maximum inclination corresponds to the angle of repose of the mean debris particle size. The exact definition of scree in the primary literature is somewhat relaxed, and it often overlaps with both ''talus'' and ''colluvium''. The term ''scree'' comes from the Old Norse term for landslide, ''skriða'', while the term ''talus'' is a French word meaning a slope or embankment. In high-altitude arctic and subarctic regions, scree slopes and talus deposits are typically adjacent to hills and river valleys. These steep slopes usually originate from late-Pleistocene periglacial processes. Notable scree sites in Eastern North America include the Ice Caves at White Rocks National Recreation Area in southern Ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yosemite National Park
Yosemite National Park ( ) is an American national park in California, surrounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an area of and sits in four County, countiescentered in Tuolumne County, California, Tuolumne and Mariposa County, California, Mariposa, extending north and east to Mono County, California, Mono and south to Madera County, California, Madera County. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, Sequoiadendron giganteum, giant sequoia groves, lakes, mountains, meadows, glaciers, and Biodiversity, biological diversity. Almost 95 percent of the park is designated National Wilderness Preservation System, wilderness. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devils Postpile National Monument
Devils Postpile National Monument is a U.S. National Monument located near Mammoth Mountain in Eastern California. The monument protects Devils Postpile, an unusual rock formation of columnar basalt, “all closely and perfectly fitted together like a vast mosaic.” The monument encompasses and includes two main attractions: the Devils Postpile formation and Rainbow Falls, a waterfall on the Middle Fork of the San Joaquin River. In addition, the John Muir Trail and Pacific Crest Trail merge into one trail as they pass through the monument. Excluding a small developed area containing the monument headquarters, visitor center and a campground, the National Monument lies within the borders of the Ansel Adams Wilderness. History The monument was established in 1911 as "Devil Postpile National Monument," (no possessive) but is widely referred to as Devils Postpile National Monument, and has been officially styled as plural without the apostrophe since the 1930s. An alternate hist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilbourne Hole Path In
Kilbourne may refer to: Places United States * Kilbourne, Illinois * Kilbourne, Louisiana * Kilbourne, Ohio United Kingdom * Kilburn, Derbyshire, historically also spelled Kilbourne Other uses * Kilbourne (DJ) * Kilbourne (surname) Kilbourne is a surname. Notable people with the surname include: * Ashe Kilbourne, DJ * Amos Kilbourne, English footballer * Charles E. Kilbourne (1872–1963), United States Army general * Edward C. Kilbourne (1856–1959) * Edwin D. Kilbourne (19 ... * Kilbourne High School, high school in Columbus, Ohio {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Surge
A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do. The speed of pyroclastic density currents has been measured directly via photography only in the case of Mount St. Helens, where they reached 320-470 km/h, or . Estimates of other modern eruptions are around 360 km/h, or 100 m/s (225 mph). Pyroclastic flows may generate surges. For example, the city of Saint-Pierre in Martinique in 1902 was overcome by one. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge. Base surge First recognized after the Taal Volcano eruption of 1965 in the Philippines, where a visiting volcanologist from USGS recognized the pheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvium
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined ''alluvion'' (the F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Country Rock (geology)
In geology, country rock is the rock native to an area, in contrast to any intrusion of viscous geologic material, commonly magma, or perhaps rock salt (in salt domes) or unconsolidated sediments. Magma is typically less dense than the rock it intrudes, widening and filling existing cracks, sometimes melting the already-existing country rock. The term "country rock" is similar to, and in many cases interchangeable with, the terms basement and wall rocks. Country rock can denote the widespread lithology of a region in relation to the rock which is being discussed or observed. Geologic settings Settings in geology when the term ''country rock'' is used include: Igneous intrusions When describing a pluton or dike, the igneous rock can be described as intruding the surrounding ''country rock'', the rock into which the pluton has intruded.Newfoundland and LabradorGlossary of Geological Terms Accessed June 2018. When country rock is intruded by a dike, perpendicular to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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