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Lechatelierite
Lechatelierite is silica glass, amorphous SiO2, non-crystalline mineraloid. It is named for Henry Louis Le Chatelier. Structure Lechatelierite is a mineraloid as it does not have a crystal structure. Although not a true mineral, it is often classified in the quartz mineral group. Formation One common way in which lechatelierite forms naturally is by very-high-temperature melting of quartz sand during a lightning strike. The result is an irregular, branching, often foamy hollow tube of silica glass called a fulgurite. Not all fulgurites are lechatelierite; the original sand must be nearly pure silica. Lechatelierite also forms as the result of high pressure shock metamorphism during meteorite impact cratering and is a common component of a type of glassy ejecta called tektites. Most tektites are blobs of impure glassy material, but tektites from the Sahara Desert in Libya and Egypt, known as '' Libyan desert glass'', are composed of almost pure silica that is almost pure lech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulgurite
Fulgurites (), commonly called "fossilized lightning", are natural tubes, clumps, or masses of sintered, vitrified, or fused soil, sand, rock, organic debris and other sediments that sometimes form when lightning discharges into ground. When composed of silica, fulgurites are classified as a variety of the mineraloid lechatelierite. When ordinary negative polarity cloud-ground lightning discharges into a grounding substrate, greater than 100 million volts (100 MV) of potential difference may be bridged. Such current may propagate into silica-rich quartzose sand, mixed soil, clay, or other sediments, rapidly vaporizing and melting resistant materials within such a common dissipation regime. This results in the formation of generally hollow and/or vesicular, branching assemblages of glassy tubes, crusts, and clumped masses. Fulgurites have no fixed composition because their chemical composition is determined by the physical and chemical properties of whatever material is bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tektite
Tektites () are gravel-sized bodies composed of black, green, brown or grey natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess (1867–1941), son of Eduard Suess. They generally range in size from millimetres to centimetres. Millimetre-scale tektites are known as microtektites.French, B. M. (1998) ''Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures.'' LPI Contribution No. 954. Lunar and Planetary Institute, Houston, Texas. 120 pp.McCall, G. J. H. (2001) ''Tektites in the Geological Record: Showers of Glass from the Sky.'' The Geological Society Publishing House, Bath, United Kingdom. 256 pp. Montanari, A., and C. Koeberl (2000) ''Impact Stratigraphy. The Italian Record.'' Lecture Notes in Earth Sciences Series no. 93. Springer-Verlag, New York, New York. 364 pp. Tektites are characterized by: # a fairly homogeneous composition # an ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineraloid
A mineraloid is a naturally occurring substance that resembles a mineral, but does not demonstrate the crystallinity of a mineral. Mineraloid substances possess chemical compositions that vary beyond the generally accepted ranges for specific minerals, for example, obsidian is an amorphous glass and not a true crystal; lignite ( jet) is derived from the decay of wood under extreme pressure underground; and opal is a mineraloid substance because of its non-crystalline nature. Pearl is a mineraloid substance because the calcite crystals and the aragonite crystals are bonded by an organic material, and naturally occurs without definite proportions of the components. The first usage of the term ''mineraloid'' substance was in 1909, by mineralogist and geologist Julian Niedzwiedzki, in identifying and describing amorphous substances that resemble minerals. Examples * Allophane, solid (IMA/CNMNC valid mineral name) * Amber, non-crystalline structure, organic * Anthracite or ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libyan Desert Glass
Libyan desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers. Like obsidian, it was knapped and used to make tools during the Pleistocene. Geologic origin The origin of desert glass is uncertain. Meteoritic origins have long been considered possible, and recent research links the glass to impact features, such as zircon breakdown, vaporized quartz and meteoritic metals, and to an impact crater. Some geologists associate the glass with radiative melting from meteoric large aerial bursts, making it analogous to trinitite created from sand exposed to the thermal radiation of a nuclear explosion. Libyan Desert glass has been dated as having formed about 29 million years ago. Analysis of samples with the electron backscatter diffraction (EBSD) technique revealed zircon Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product. Examples include fused quartz, fumed silica, opal, and aerogels. It is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries. All forms are white or colorless, although impure samples can be colored. Silicon dioxide is a common fundamental constituent of glass. Structure In the majority of silicon dioxides, the silicon atom shows Tetrahedral molecular geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egypt
Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northern coast of Egypt, the north, the Gaza Strip of Palestine and Israel to Egypt–Israel barrier, the northeast, the Red Sea to the east, Sudan to Egypt–Sudan border, the south, and Libya to Egypt–Libya border, the west; the Gulf of Aqaba in the northeast separates Egypt from Jordan and Saudi Arabia. Cairo is the capital, list of cities and towns in Egypt, largest city, and leading cultural center, while Alexandria is the second-largest city and an important hub of industry and tourism. With over 109 million inhabitants, Egypt is the List of African countries by population, third-most populous country in Africa and List of countries and dependencies by population, 15th-most populated in the world. Egypt has one of the longest histories o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Sands, New Mexico
White Sands is a census-designated place (CDP) in Doña Ana County, New Mexico, United States. It consists of the main residential area on the White Sands Missile Range. As of the 2010 census the population of the CDP was 1,651. It is part of the Las Cruces Metropolitan Statistical Area. Geography The White Sands CDP is located in eastern Doña Ana County at the southern end of the White Sands Missile Range. It is south of U.S. Route 70 and east of Las Cruces, the county seat. The entrance to White Sands National Park is to the northeast, up US 70. According to the United States Census Bureau, the CDP has a total area of , all land. Demographics As of the census of 2000, there were 1,323 people, 432 households, and 355 families residing in the CDP. The population density was . There were 667 housing units at an average density of . The racial makeup of the CDP was 71.43% White, 11.56% African American, 0.98% Native American, 3.70% Asian, 0.08% Pacific Islander, 6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trinitite
Trinitite, also known as atomsite or Alamogordo glass, is the glassy residue left on the desert floor after the plutonium-based Trinity (nuclear test), Trinity nuclear bomb test on July 16, 1945, near Alamogordo, New Mexico. The glass is primarily made of Arkose, arkosic sand composed of quartz grains and feldspar (both microcline and smaller amount of plagioclase with small amount of calcite, hornblende and augite in a Matrix (geology), matrix of sandy clay) that was melted by the atomic blast. It was first academically described in ''American Mineralogist'' in 1948. It is usually a light green, although red trinitite was also found in one section of the blast site, and rare pieces of black trinitite formed. It is mildly radioactive but safe to handle. Pieces of the material remain at the Trinity site , although most of it was bulldozed and buried by the United States Atomic Energy Commission in 1953. Formation In 2005 it was theorized by Los Alamos National Laboratory scienti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Museum Of Natural History
The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconnected buildings housing 45 permanent exhibition halls, in addition to a planetarium and a library. The museum collections contain about 32 million specimens of plants, animals, fungi, fossils, minerals, rocks, meteorites, human remains, and human cultural artifacts, as well as specialized collections for frozen tissue and genomic and astrophysical data, of which only a small fraction can be displayed at any given time. The museum occupies more than . AMNH has a full-time scientific staff of 225, sponsors over 120 special field expeditions each year, and averages about five million visits annually. The AMNH is a private 501(c)(3) organization. The naturalist Albert S. Bickmore devised the idea for the American Museum of Natural History in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arizona
Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the northwest and California to the west, and shares Mexico-United States border, an international border with the Mexican states of Sonora and Baja California to the south and southwest. Its Capital city, capital and List of largest cities, largest city is Phoenix, Arizona, Phoenix, which is the most populous state capital and list of United States cities by population, fifth most populous city in the United States. Arizona is divided into 15 List of counties in Arizona, counties. Arizona is the list of U.S. states and territories by area, 6th-largest state by area and the list of U.S. states and territories by population, 14th-most-populous of the 50 states. It is the 48th state and last of the contiguous United States, contiguous states to be a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteor Crater
Meteor Crater, or Barringer Crater, is an impact crater about east of Flagstaff and west of Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fragments of the meteorite are officially called the Canyon Diablo Meteorite, after the adjacent Canyon Diablo. Meteor Crater lies at an elevation of above sea level. It is about in diameter, some deep, and is surrounded by a rim that rises above the surrounding plains. The center of the crater is filled with of rubble lying above crater bedrock. One of the features of the crater is its squared-off outline, believed to be caused by existing regional jointing (cracks) in the strata at the impact site. Despite an attempt to make the crater a public landmark, the crater remains privately owned by the Barringer family to the present day through their Barringer Crater Company. The Lunar and Planetary Institute, the American Museum of Natural History, and other science institutes pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coconino Sandstone
The Coconino Sandstone is a geologic formation (geology), formation composed of light-colored quartz arenite of Aeolian processes, eolian origin. It erodes to form conspicuous, sheer cliffs in the upper walls of Grand Canyon, as part of the Mogollon Rim to the south and east, and in many other parts of the Colorado Plateau region. The Coconino Sandstone is well known for its fossil trackways of Terrestrial animal, terrestrial invertebrates and vertebrates and Cross-bedding, large-scale cross-stratification.Middleton, L.T., D.K. Elliott, and M. Morales (2002) ''Coconino Sandstone,'' in S.S. Beus and M. Morales, eds., ''Grand Canyon Geology.'' Oxford University Press, New York. Eastward of a north–south line from Monument Creek to Fossil Creek, the Coconino Sandstone overlies and interfingers with and grades into the Schnebly Hill Formation, which is equivalent in part to the De Chelly Sandstone in Utah. In this area, it underlies the Kaibab Limestone. Further eastward, the Coc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
