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Picrite
Picrite basalt or picrobasalt is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine. It is dark with yellow-green olivine phenocrysts (20-50%) and black to dark brown pyroxene, mostly augite. The olivine-rich picrite basalts that occur with the more common tholeiitic basalts of Kīlauea and other volcanoes of the Hawaiian Islands are the result of accumulation of olivine crystals either in a portion of the magma chamber or in a caldera lava lake. The compositions of these rocks are well represented by mixes of olivine and more typical tholeiitic basalt. The name "picrite" can also be applied to an olivine-rich alkali basalt: such picrite consists largely of phenocrysts of olivine and titanium-rich augite pyroxene with minor plagioclase set in a groundmass of augite and more sodic plagioclase and perhaps analcite and biotite. Picrites and komatiites are somewhat similar chemically (defined as >18% MgO), but differ in having 1 to 2% total alkalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanite Grand Brule Dsc03601
Picrite basalt or picrobasalt is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine. It is dark with yellow-green olivine phenocrysts (20-50%) and black to dark brown pyroxene, mostly augite. The olivine-rich picrite basalts that occur with the more common tholeiitic basalts of Kīlauea and other volcanoes of the Hawaiian Islands are the result of accumulation of olivine crystals either in a portion of the magma chamber or in a caldera lava lake. The compositions of these rocks are well represented by mixes of olivine and more typical tholeiitic basalt. The name "picrite" can also be applied to an olivine-rich alkali basalt: such picrite consists largely of phenocrysts of olivine and titanium-rich augite pyroxene with minor plagioclase set in a groundmass of augite and more sodic plagioclase and perhaps analcite and biotite. Picrites and komatiites are somewhat similar chemically (defined as >18% MgO), but differ in having 1 to 2% total alkalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultramafic Rocks
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. Intrusive ultramafic rocks Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types do not represent the chemistry of the magma from which they crystallized. The ultramafic intrusives include the dunites, peridotites and pyroxenites. Other rare varieties include troctolite which has a greater percentag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Komatiite
Komatiite () is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% MgO. Komatiites have low silicon, potassium and aluminium, and high to extremely high magnesium content. Komatiite was named for its type locality along the Komati River in South Africa, and frequently displays spinifex texture composed of large dendritic plates of olivine and pyroxene. Komatiites are rare rocks; almost all komatiites were formed during the Archaean Eon (4.0–2.5 billion years ago), with few younger (Proterozoic or Phanerozoic) examples known. This restriction in age is thought to be due to cooling of the mantle, which may have been hotter during the Archaean. The early Earth had much higher heat production, due to the residual heat from planetary accretion, as well as the greater abundance of radioactive isotopes, particularly shorter lived ones like uranium 235 which produce more decay heat. Lower temperature mantle melts such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mafic Rocks
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase feldspar. Mafic materials can also be described as ferromagnesian. History The term ''mafic'' is a portmanteau of "magnesium" and "ferric" and was coined by Charles Whitman Cross, Joseph P. Iddings, Louis Valentine Pirsson, and Henry Stephens Washington in 1912. Cross' group had previously divided the major rock-forming minerals found in igneous rocks into ''salic'' minerals, such as quartz, feldspars, or feldspathoids, and ''femic'' minerals, such as olivine and pyroxene. However, micas and aluminium-rich amphiboles were excluded, while some calcium minerals containing little iron or magnesium, such as wollastonite or apatite, were included i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphanitic Rocks
Aphanites (adj. ''aphanitic''; ) are igneous rocks that are so fine-grained that their component mineral crystals are not visible to the naked eye (in contrast to phanerites, in which the crystals are visible to the unaided eye). This geological texture results from rapid cooling in volcanic or hypabyssal (shallow subsurface) environments. As a rule, the texture of these rocks is not the same as that of volcanic glass (e.g., obsidian), with volcanic glass being non-crystalline (amorphous), and having a glass-like appearance.{{cite book , author=Bates and Jackson , year=1984 , title=Dictionary of Geological Terms , edition=3rd , publisher=American Geological Institute Aphanites are commonly porphyritic, having large crystals embedded in the fine groundmass, or matrix. The larger inclusions are called phenocrysts. They consist essentially of very small crystals of minerals such as plagioclase feldspar, with hornblende or augite, and may contain also biotite, quartz, and orthocl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Geophysical Union
The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences. The geophysical sciences involve four fundamental areas: atmospheric and ocean sciences; solid-Earth sciences; hydrologic sciences; and space sciences. The organization's headquarters is located on Florida Avenue in Washington, D.C. History The AGU was established in December 1919 by the National Research Council (NRC) to represent the United States in the International Union of Geodesy and Geophysics (IUGG), and its first chairman was William Bowie of the United States Coast and Geodetic Survey (USCGS). For more than 50 years, it operated as an unincorporated affili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw-Hill
McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes reference and trade publications for the medical, business, and engineering professions. McGraw Hill operates in 28 countries, has about 4,000 employees globally, and offers products and services to about 140 countries in about 60 languages. Formerly a division of The McGraw Hill Companies (later renamed McGraw Hill Financial, now S&P Global), McGraw Hill Education was divested and acquired by Apollo Global Management in March 2013 for $2.4 billion in cash. McGraw Hill was sold in 2021 to Platinum Equity for $4.5 billion. Corporate History McGraw Hill was founded in 1888 when James H. McGraw, co-founder of the company, purchased the ''American Journal of Railway Appliances''. He continued to add further publications, eventually establishing The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antoine Lacroix
Antoine François Alfred Lacroix (4 February 186312 March 1948) was a French mineralogist and geologist. He was born in Mâcon, Saône-et-Loire. Education Lacroix completed a D. s Sc. in Paris in 1889, as student of Ferdinand André Fouqué. Fouqué only agreed to the graduation if Lacroix would marry his daughter. Career In 1893, he was appointed professor of mineralogy at the Jardin des Plantes, Paris, and in 1896 director of the mineralogical laboratory in the École des Hautes Études. He paid especial attention to minerals connected with volcanic phenomena and igneous rocks, to the effects of metamorphism, and to mineral veins, in various parts of the world, notably in the Pyrenees. In his numerous contributions to scientific journals he dealt with the mineralogy and petrology of Madagascar, and published an elaborate and exhaustive volume on the eruptions in Martinique, ''La Montagne Pelée et ses éruptions'' (Paris 1904). He also issued an important work entitled ''Mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Réunion Island
Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island of Madagascar and southwest of the island of Mauritius. , it had a population of 868,846. Like the other four overseas departments, Réunion also holds the status of a region of France, and is an integral part of the French Republic. Réunion is an outermost region of the European Union and is part of the eurozone. Réunion and the fellow French overseas department of Mayotte are the only eurozone regions located in the Southern Hemisphere. As in the rest of France, the official language of Réunion is French. In addition, a majority of the region's population speaks Réunion Creole. Toponymy When France took possession of the island in the seventeenth century, it was named Bourbon, after the dynasty that then ruled France. To break ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piton De La Fournaise
Piton de la Fournaise (; en, "Peak of the Furnace") is a shield volcano on the eastern side of Réunion island (a French overseas department and region) in the Indian Ocean. It is currently one of the most active volcanoes in the world, along with Kīlauea in the Hawaiian Islands, Stromboli and Etna in Italy and Mount Erebus in Antarctica. A previous eruption began in August 2006 and ended in January 2007. The volcano erupted again in February 2007, on 21 September 2008, on 9 December 2010, which lasted for two days, and on 1 August 2015. The most recent eruption began on 7 December 2020. The volcano is located within Réunion National Park, a World Heritage Site. Residents of Réunion sometimes refer to Piton de la Fournaise simply as ''le Volcan'' ("the Volcano"). It is a major tourist attraction on Réunion island. Geology The uppermost section of the volcano is occupied by the Enclos Fouqué, a caldera wide. High cliffs, known as ''remparts'' in French, form the calder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curaçao
Curaçao ( ; ; pap, Kòrsou, ), officially the Country of Curaçao ( nl, Land Curaçao; pap, Pais Kòrsou), is a Lesser Antilles island country in the southern Caribbean Sea and the Dutch Caribbean region, about north of the Venezuela coast. It is a constituent country of the Kingdom of the Netherlands. Together with Aruba and Bonaire, it forms the ABC islands. Collectively, Curaçao, Aruba, and other Dutch islands in the Caribbean are often called the Dutch Caribbean. Curaçao was formerly part of the Curaçao and Dependencies colony from 1815 to 1954 and later the Netherlands Antilles from 1954 to 2010, as Island Territory of Curaçao ( nl, Eilandgebied Curaçao, links=no, pap, Teritorio Insular di Kòrsou, links=no), and is now formally called the Country of Curaçao. It includes the main island of Curaçao and the much smaller, uninhabited island of Klein Curaçao ("Little Curaçao"). Curaçao has a population of 158,665 (January 2019 est.), with an area of ; its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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