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Erebus Crystal
An erebus crystal is a crystal of anorthoclase (a type of feldspar) found in the immediate area surrounding Mount Erebus near McMurdo Station, Antarctica. This type of feldspar is rich in sodium, potassium, and aluminium silicate. Similar crystals have also been reported on Mount Kenya and Mount Kilimanjaro. Though the formation and growth of these crystals is not well understood, it is evident that the crystals grow in the magma beneath Mount Erebus and are ejected out of the mountain encased in glassy volcanic bombs. This glass structure quickly weathers away leaving the mountainside covered in crystals. References {{reflist Triclinic minerals Feldspar Geology of Antarctica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word ''crystal'' derives from the Ancient Greek word (), meaning both "ice" and "rock crystal", from (), "icy cold, frost". Examples of large crystals include snowflakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Polycrystals include most metals, rocks, ceramics, and ice. A third category of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anorthoclase
The mineral anorthoclase ((Na,K)AlSi3O8) is a crystalline solid solution in the alkali feldspar series, in which the sodium-aluminium silicate member exists in larger proportion. It typically consists of between 10 and 36 percent of KAlSi3O8 and between 64 and 90 percent of NaAlSi3O8.Deere, Howie and Zussman, ''Rock Forming Minerals,'' Vol. 4 ''Framework Silicates,'' Wiley, pp. 2 - 5, Fig. 1 Structure and stability Anorthoclase is an intermediate member of the high albite – sanidine alkali feldspar solid solution series. Intermediate members of this series, high albite, anorthoclase and high sodium sanidine are stable at temperatures of and above. Below 400 to 600 °C only very limited solution exists (less than about 5% on both the low albite and microcline ends).Klein, Cornelis and Cornelius S. Hurlbut, Jr. ''Handbook of Mineralogy,'' Wiley, pp. 446-449 (Fig. 11-95 Anorthoclase and high albite exhibit triclinic symmetry, whereas sanidine and the low temperature orthoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by weight. Feldspars crystalize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Compositions The feldspar group of minerals consists of tectosilicates, silicate minerals in which silicon ions are linked by shared oxygen ions to form a three-dimensional network. Compositions of major elements in common feldspars can be expressed in terms of three endmembers: * potassium feldspar (K-spar) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Erebus
Mount Erebus () is the second-highest volcano in Antarctica (after Mount Sidley), the highest active volcano in Antarctica, and the southernmost active volcano on Earth. It is the sixth-highest ultra mountain on the continent. With a summit elevation of , it is located in the Ross Dependency on Ross Island, which is also home to three inactive volcanoes: Mount Terror, Mount Bird, and Mount Terra Nova. The volcano has been active since about 1.3 million years ago and has a long-lived lava lake in its inner summit crater that has been present since at least the early 1970s. The volcano was the site of the Air New Zealand Flight 901 accident, which occurred in November 1979. Geology and volcanology Mount Erebus is the world's southernmost active volcano. It is the current eruptive centre of the Erebus hotspot. The summit contains a persistent convecting phonolitic lava lake, one of five long-lasting lava lakes on Earth. Characteristic eruptive activity consists of Str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McMurdo Station
McMurdo Station is a United States Antarctic research station on the south tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program (USAP), a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as one of three year-round United States Antarctic science facilities. All personnel and cargo going to or coming from Amundsen–Scott South Pole Station first pass through McMurdo. By road, McMurdo is 3 kilometres (1.9 mi) from New Zealand's smaller Scott Base. History The station takes its name from its geographic location on McMurdo Sound, named after Lieutenant Archibald McMurdo of . The ''Terror'', commanded by Irish explorer Francis Crozier, along with expedition flagship ''Erebus'' under command of James Clark Ross, first charted the area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where vegetation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac- colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Silicate
Aluminium silicate (or aluminum silicate) is a name commonly applied to chemical compounds which are derived from aluminium oxide, Al2O3 and silicon dioxide, SiO2 which may be anhydrous or hydrated, naturally occurring as minerals or synthetic. Their chemical formulae are often expressed as xAl2O3·ySiO2·zH2O. It is known as E number E559. Examples * Al2SiO5, (Al2O3·SiO2), which occurs naturally as the minerals andalusite, kyanite and sillimanite which have different crystal structures. * Al2Si2O5(OH)4, (Al2O3·2SiO2·2H2O), which occurs naturally as the mineral kaolinite and is also called aluminium silicate dihydrate.Handbook of Inorganic Compounds, Dale L. Perry, Taylor & Francis, 2011, It is a fine white powder and is used as a filler in paper and rubber and also used in paints. * Al2Si2O7, (Al2O3·2SiO2), called metakaolinite, formed from kaolin by heating at . * Al6Si2O13, (3Al2O3·2SiO2), the mineral mullite, the only thermodynamically stable intermediate phase in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Kenya
Mount Kenya (Kikuyu: ''Kĩrĩnyaga'', Kamba, ''Ki Nyaa'') is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian (), Nelion () and Point Lenana (). Mount Kenya is located in the former Eastern and Central provinces of Kenya; its peak is now the intersection of Meru, Embu, Laikipia, Kirinyaga, Nyeri and Tharaka Nithi counties, about south of the equator, around north-northeast of the capital Nairobi. Mount Kenya is the source of the name of the Republic of Kenya. Mount Kenya is a volcano created approximately 3 million years after the opening of the East African Rift. Before glaciation, it was high. It was covered by an ice cap for thousands of years. This has resulted in very eroded slopes and numerous valleys radiating from the peak. There are currently 11 small glaciers, which are shrinking rapidly, and may disappear by 2050. The forested slopes are an important source of water for much of Keny ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Kilimanjaro
Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest free-standing mountain above sea level in the world: above sea level and about above its plateau base. It is the highest volcano in Africa and the Eastern Hemisphere. Kilimanjaro is the fourth most topographically prominent peak on Earth. It is part of Kilimanjaro National Park and is a major hiking and climbing destination. Because of its shrinking glaciers and ice fields, which are projected to disappear between 2025 and 2035, it has been the subject of many scientific studies. Toponymy The origin of the name Kilimanjaro is not known, but a number of theories exist. European explorers had adopted the name by 1860 and reported that Kilimanjaro was the mountain's Kiswahili name. The 1907 edition of ''The Nuttall Encyclopædia'' also records the name of the mountain as Kilima-Njaro. Johann Ludwig Krapf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
