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Encyclopedia > Basalt
Basalt
Basalt

Basalt (pronounced /ˈbæsɒlt, bəˈsɔːlt/) is a common gray to black extrusive volcanic rock. It is usually fine-grained due to rapid cooling of lava on the Earth's surface. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or gray. Image File history File links This is a lossless scalable vector image. ... Basalt is a town located in Eagle County, Colorado. ... Basalt is a city in Bingham County, Idaho, United States. ... This is a file from the Wikimedia Commons, a repository of free content hosted by the Wikimedia Foundation. ... This is a file from the Wikimedia Commons, a repository of free content hosted by the Wikimedia Foundation. ... Extrusive refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. ... Ignimbrite is a deposit of a pyroclastic flow. ... Look up lava, Aa, pahoehoe in Wiktionary, the free dictionary. ... (For other meanings of Porphyr, see Porphyry) The baptismal font in the Cathedral of Magdeburg is made of rose porphyry from a site near Assuan, Egypt Porphyry is a very hard red, green or purple igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a... The matrix or groundmass of an igneous rock consists of fine grained often microscopic crystals in which larger crystals (phenocrysts) are embedded. ... Vesicular texture is a volcanic rock texture characterised by, or containing, many vesicles. ... Scoria Scoria is a textural term for macrovesicular volcanic rock ejecta. ...


Basalt magmas have formed by decompression melting of the Earth's mantle and by partial melting of rock in the interiors of Mars and the Earth's moon. Source rocks for the partial melts probably include both peridotite and pyroxenite (e.g., Sobolev et al., 2007). The crustal portions of oceanic tectonic plates are composed predominantly of basalt, produced from upwelling mantle below ocean ridges. Volcanic rock in North America Plutonic rock in North America Igneous rocks (etymology from Latin ignis, fire) are rocks formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Earth cutaway from core to exosphere. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... This article is about Earths moon. ... Peridotite xenolith from San Carlos, southwestern United States. ... Pyroxenite is a rock consisting essentially of minerals of the pyroxene group, such as augite and diallage, hypersthene, bronzite or enstatite. ... Earth cutaway from core to exosphere. ... Animated map exhibiting the worlds oceanic waters. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... An oceanic ridge is an underwater mountain range, usually formed by plate tectonics. ...


The term basalt is at times applied to shallow intrusive rocks with a composition typical of basalt, but rocks of this composition with a phaneritic (coarse) groundmass are generally referred to as dolerite (also called diabase) or gabbro. Pluton redirects here. ... Granite is typical phaneritic igneous rock. ... It has been suggested that this article or section be merged with Diabase. ... It has been suggested that this article or section be merged with Dolerite. ... Gabbro specimen. ...

Columnar basalt at Sheepeater Cliff in Yellowstone

Contents

Photo taken by Daniel Mayer and released under terms of the GNU FDL. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Photo taken by Daniel Mayer and released under terms of the GNU FDL. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

Types of basalt

Large masses must cool slowly to form a polygonal fracture pattern
Large masses must cool slowly to form a polygonal fracture pattern
  • Tholeiitic basalt is relatively poor in silica and poor in sodium. Included in this category are most basalts of the ocean floor, most large oceanic islands, and continental flood basalts such as the Columbia River Plateau.
    • MORB (Mid Ocean Ridge Basalt), is characteristically low in incompatible elements. MORB is commonly erupted only at ocean ridges. MORB itself has been subdivided into varieties such as NMORB and EMORB (slightly more enriched in incompatible elements).[1] [2]
  • High alumina basalt may be silica-undersaturated or -oversaturated (see normative mineralogy). It has greater than 17% alumina (Al2O3) and is intermediate in composition between tholeiite and alkali basalt; the relatively alumina-rich composition is based on rocks without phenocrysts of plagioclase.
  • Boninite is a high-magnesium form of basalt or andesite that is erupted generally in back-arc basins, distinguished by its low titanium content and trace element composition.

Close up of Giants Causeway. ... Close up of Giants Causeway. ... Tholeiite (or the preferred name, tholeiitic basalt) is an igneous rock, a type of basalt. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... For sodium in the diet, see Edible salt. ... Animated map exhibiting the worlds oceanic waters. ... Moses Coulee showing multiple flood basalt flows of the Columbia River Basalt Group. ... The Columbia River Basalt Group encompasses portions of 3 states. ... Oceanic Ridge Oceanic crust is formed at an oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches. ... Incompatible element is a term used in petrology and geochemistry. ... Normative mineralogy is a geochemical calculation of the whole rock geochemistry of a rock sample which estimates the idealised mineralogy of a rock according to the principles of geochemistry. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Example of phenocrysts in rhomb porphyry from the Oslo rift area in Norway A phenocryst is a relatively large and usually conspicuous crystal formed in the mass of a porphyritic igneous rock. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Normative mineralogy is a geochemical calculation of the whole rock geochemistry of a rock sample which estimates the idealised mineralogy of a rock according to the principles of geochemistry. ... The feldspathoids are a group of tectosilicate minerals which resemble feldspars but have a different structure and much lower silica content. ... Alkaline redirects here. ... This article does not cite any references or sources. ... Phlogopite is a yellow, greenish or reddish brown member of the mica family of phyllosilicates. ... Boninite is a high magnesium mafic extrusive rock formed in back-arc environments, typically in seafloor spreading centres but also in terrestrial back-arc spreading centres. ... A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. ... Back-arc basins (or retro-arc basins) are geologic features, submarine basins associated with island arcs and subduction zones. ... General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ...

Petrology

The mineralogy of basalt is characterized by a preponderance of calcic plagioclase feldspar and pyroxene. Olivine can also be a significant constituent. Accessory minerals present in relatively minor amounts include iron oxides and iron-titanium oxides, such as magnetite, ulvospinel, and ilmenite. Because of the presence of such oxide minerals, basalt can acquire strong magnetic signatures as it cools, and paleomagnetic studies have made extensive use of basalt. Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... This article does not cite any references or sources. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... For other uses, see Mineral (disambiguation). ... Iron oxide pigment There are a number of iron oxides: Iron oxides Iron(II) oxide or ferrous oxide (FeO) The black-coloured powder in particular can cause explosions as it readily ignites. ... Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. ... ... Ilmenite is a weakly magnetic iron-black or steel-gray mineral found in metamorphic and igneous rocks. ... An oxide is a chemical compound containing at least one oxygen atom and other elements. ... In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... Paleomagnetism refers to the study of the record of the Earths magnetic field preserved in various magnetic minerals through time. ...


In tholeiitic basalt, pyroxene (augite and orthopyroxene or pigeonite) and calcium-rich plagioclase are common phenocryst minerals. Olivine may also be a phenocryst, and when present, may have rims of pigeonite. The groundmass contains interstitial quartz or tridymite or cristobalite. Olivine tholeiite has augite and orthopyroxene or pigeonite with abundant olivine, but olivine may have rims of pyroxene and is unlikely to be present in the groundmass. Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... Augite is a single chain inosilicate mineral described chemically as (Ca,Mg,Fe)SiO3 or calcium magnesium iron silicate. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... This page meets Wikipedias criteria for speedy deletion. ... For other uses, see Calcium (disambiguation). ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Example of phenocrysts in rhomb porphyry from the Oslo rift area in Norway A phenocryst is a relatively large and usually conspicuous crystal formed in the mass of a porphyritic igneous rock. ... This page meets Wikipedias criteria for speedy deletion. ... The matrix or groundmass of rock is the fine-grained mass of material in which larger grains or crystals are embedded. ... For other uses, see Quartz (disambiguation). ... Tridymite Tridymite is a high-temperature polymorph of quartz and usually occurs as minute tabular white or colorless pseudo-hexagonal triclinic crystals, or scales, in cavities in acidic volcanic rocks. ... Common in volcanic rocks, cristobalite is a high-temperature polymorph of quartz and tridymite. ... The matrix or groundmass of an igneous rock consists of fine grained often microscopic crystals in which larger crystals (phenocrysts) are embedded. ...


In high-alumina basalts, phenocrysts of feldspar commonly are bytownite in composition. Other common phenocryst minerals are olivine and augite; orthopyroxene is less common. Silica minerals and/or alkali feldspar may be present in the groundmass. Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... This article does not cite any references or sources. ...


Alkali basalts typically have mineral assemblages that lack orthopyroxene but contain olivine. Feldspar phenocrysts typically are labradorite to andesine in composition. Augite is rich in titanium compared to augite in tholeiitic basalt. Minerals such as alkali feldspar, leucite, nepheline, sodalite, phlogopite mica, and apatite may be present in the groundmass. Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... Labradorite, a feldspar mineral, is a member of the plagioclase series. ... Andesine is a feldspar mineral, a part of the plagioclase series. ... Augite is a single chain inosilicate mineral described chemically as (Ca,Mg,Fe)SiO3 or calcium magnesium iron silicate. ... This article does not cite any references or sources. ... Leucite or amphigene is a rock-forming mineral composed of potassium and aluminium metasilicate KAl(SiO3)2. ... A big crystal of Nepheline from Canaã Massif, Brazil Nepheline, also called nephelite (from Greek: nephos, cloud), is a feldspathoid: a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites. ... Sodalite is a rare, rich royal blue mineral widely enjoyed as an ornamental stone. ... Phlogopite is a yellow, greenish or reddish brown member of the mica family of phyllosilicates. ... Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, and chlorapatite, named for high concentrations of OH-, F-, or Cl- ions, respectively, in the crystal. ...


Basalt has high liquidus and solidus temperatures -- values at the Earth's surface are near or above 1200 °C (liquidus) and near or below 1000 °C (solidus); these values are higher than those of other common igneous rocks. In chemistry, materials science, and physics, the liquidus is a line on a phase diagram above which a given substance is stable in the liquid phase. ... Solidus (Latin) is the name of a Roman coin during the Roman Empire. ... Volcanic rock in North America Plutonic rock in North America Igneous rocks (etymology from Latin ignis, fire) are rocks formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ...


The majority of tholeiites are formed at approximately 50-100 km depth within the mantle. Many alkali basalts may be formed at greater depths, perhaps as deep as 150-200 km. The origin of high-alumina basalt continues to be controversial, with interpretations that it is a primary melt and that instead it is derived from other basalt types (e.g., Ozerov, 2000). Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ...


Geochemistry

Basalt compositions are rich in MgO and CaO and low in SiO2 and Na2O plus K2O relative to most common igneous rocks, consistent with the TAS classification. Magnesium oxide, or magnesia, is a white solid mineral that occurs naturally as periclase and is a source of magnesium. ... Calcium oxide (CaO), commonly known as lime, quicklime or burnt lime, is a widely used chemical compound. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... Sodium oxide is a chemical compound with the formula Na2O. It is used in ceramics and glasses. ... Potassium oxide is a compound of potassium and oxygen used mainly as a intermediate in inorganic synthesis. ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... The TAS classification can be used to assign names to many common types of volcanic rocks based upon the relationships between the combined alkali content and the silica content. ...


Basalt generally has a composition of 45-55 wt% SiO2, 2-6 wt% total alkalis, 0.5-2.0 wt% TiO2, 5-14 wt% FeO and 14 wt% or more Al2O3. Contents of CaO are commonly near 10 wt%, those of MgO commonly in the range 5 to 12 wt%. Flash point non-flammable Related Compounds Other cations Titanium(II) oxide Titanium(III) oxide Titanium(III,IV) oxide Zirconium dioxide Hafnium dioxide Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Titanium dioxide, also known as titanium... Iron(II) oxide, also called ferrous oxide, is a black-colored powder with the chemical formula FeO. It consists of the element iron in the oxidation state of 2 bonded to oxygen. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ...


High alumina basalts have aluminium contents of 17-19 wt% Al2O3; boninites have magnesium contents of up to 15% MgO. Rare feldspathoid-rich mafic rocks, akin to alkali basalts, may have Na2O plus K2O contents of 12% or more. The feldspathoids are a group of tectosilicate minerals which resemble feldspars but have a different structure and much lower silica content. ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ...


MORB basalts and their intrusive equivalents, gabbros, are the characteristic igneous rocks formed at mid-ocean ridges. They are tholeiites particularly low in total alkalis and in incompatible trace elements, and they have relatively flat REE patterns normalised to mantle or chondrite values. In contrast, alkali basalts have normalized patterns highly enriched in the light REE, and with greater abundances of the REE and of other incompatible elements. Because MORB basalt is considered a key to understanding plate tectonics, its compositions have been much studied. Although MORB compositions are distinctive relative to average compositions of basalts erupted in other environments, they are not uniform. For instance, compositions change with position along the Mid-Atlantic ridge, and the compositions also define different ranges in different ocean basins (Hofmann, 2003). Gabbro specimen. ... Oceanic Ridge Oceanic crust is formed at an oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches. ... Tholeiite (or Tholeiitic basalt) is a type of basalt rock that is olivine-poor, and dominated by clinopyroxene, plagioclase, and iron ore. ... The term compatibility has the following meanings: In telecommunication, the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference. ... de;Metalle der Seltenen Erden Categories: Stub | Chemical element groups ... A specimen of the NWA 869 chondrite (type L4-6), showing chondrules and metal flakes Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. ... The term compatibility has the following meanings: In telecommunication, the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... Courtesy USGS The ridge was central in the breakup of Pangaea that began some 180 million years ago. ...


Isotope ratios of elements such as strontium, neodymium, lead, hafnium, and osmium in basalts have been much-studied, so as to learn about evolution of the Earth's mantle. Isotopic ratios of noble gases, such as 3He/4He, are also of great value: for instance, ratios for basalts range from 6 to 10 for mid-ocean ridge tholeiite (normalized to atmospheric values), but to 15-24+ for ocean island basalts thought to be derived from mantle plumes. For other uses, see Isotope (disambiguation). ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Standard atomic weight 87. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Standard atomic weight 144. ... General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... General Name, Symbol, Number hafnium, Hf, 72 Chemical series transition metals Group, Period, Block 4, 6, d Appearance grey steel Standard atomic weight 178. ... General Name, Symbol, Number osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Standard atomic weight 190. ... Earth cutaway from core to exosphere. ... The noble gases are a chemical series. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... A lava lamp illustrates the basic concept of a mantle plume. ...


Morphology and textures

The shape, structure and texture of a basalt is diagnostic of how and where it erupted - whether into the sea, in an explosive cinder eruption or as creeping pahoehoe lava flows, the classical image of Hawaiian basalt eruptions. Rock microstructure includes the texture of a rock and the small scale rock structures. ... A cinder is a fragment of cooled pyroclastic material (lava or magma). ... Lava is molten rock that a volcano expels during an eruption. ... This article is about the U.S. State. ...

Columnar jointed basalt in Turkey

Image File history File links Download high resolution version (2304x1728, 1708 KB)Basalt Columns in Boyabat Province, Sinop, Turkey (Black Sea Region). ... Image File history File links Download high resolution version (2304x1728, 1708 KB)Basalt Columns in Boyabat Province, Sinop, Turkey (Black Sea Region). ... Columnar jointed basalt in Turkey Columnar jointing in the basalt of the Giants Causeway in Ireland A joint is a generally planar fracture formed in a rock as a result of extensional stress. ...

Subaerial eruptions

Basalt which erupts under open air (that is, subaerially) forms three distinct types of lava or volcanic deposits: scoria, ash or cinder; breccia and lava flows. The term subaerial, mainly used in geology, describes events or structures located at the Earths surface, under the air. This is to be contrasted with submarine events or structures, those located under the sea. ... Ash plume from Mt Cleveland, a stratovolcano Diamond Head, a well-known backdrop to Waikiki in Hawaii, is an ash cone that solidified into tuff Volcanic ash consists of very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. ... Breccia, derived from the Latin word for broken, is a sedimentary rock composed of angular fragments in a matrix that may be of a similar or a different material. ...


Basalt in the tops of subaerial lava flows and cinder cones will often be highly vesiculated, imparting a lightweight "frothy" texture to the rock. Basaltic cinders are often red, coloured by oxidised iron from weathered iron-rich minerals such as pyroxene. For peaks named Cinder Cone, see list of peaks named Cinder Cone. ... Vesicular texture is a volcanic rock texture characterised by, or containing, many vesicles. ... For other uses, see Iron (disambiguation). ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ...


‘A‘a types of blocky, cinder and breccia flows of thick, viscous basaltic lava are common in Hawaii. Pahoehoe is a highly fluid, hot form of basalt which tends to form thin aprons of molten lava which fill up hollows and sometimes forms lava lakes. Lava tubes are common features of pahoehoe eruptions. Look up lava, Aa, and pahoehoe in Wiktionary, the free dictionary. ... Look up lava, Aa, pahoehoe in Wiktionary, the free dictionary. ... Lava is molten rock that a volcano expels during an eruption. ... A lava lake in Hawaii Lava lakes are large volumes of molten lava, usually basaltic, contained in a vent, volcanic crater, or broad depression. ... Thurston Lava Tube in Hawaii Volcanoes National Park. ...


Basaltic tuff or pyroclastic rocks are rare but not unknown. Usually basalt is too hot and fluid to build up sufficient pressure to form explosive lava eruptions but occasionally this will happen by trapping of the lava within the volcanic throat and build up of volcanic gases. Hawaii's Mauna Loa volcano erupted in this way in the 19th century, as did Mount Tarawera, New Zealand in its violent 1886 eruption. Another example is the 0.2 Ma Diamond Head Tuff, Hawaii. Welded tuff at Golden Gate in Yellowstone National Park Tuff (from the Italian tufo) is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. ... Pyroclastic rocks are formed from lavas which are ejected into the air, as occur in pyroclastic flows or Plinian eruptions. ... Volcanic gases include a variety of substances given off by active (or, at times, by dormant) volcanos. ... For other uses, see Mauna Loa (disambiguation). ... Mount Tarawera is a volcanic mountain 24 kilometres southeast of Rotorua in the North Island of New Zealand. ... Mega-annum, usually abbreviated as Ma, is a unit of time equal to one million years. ... For other uses, see Diamond Head (disambiguation). ...

Columnar jointing in the basalt of the Giant's Causeway in Northern Ireland
Columnar jointing in the basalt of the Giant's Causeway in Northern Ireland

Maar volcanoes are typical of small basalt tuffs, formed by explosive eruption of basalt through the crust, forming an apron of mixed basalt and wall rock breccia and a fan of basalt tuff further out from the volcano. Image File history File linksMetadata Download high resolution version (1024x768, 282 KB) Summary Hexagonal basaltic stones at the Giants Causeway in Nothern Ireland co. ... Image File history File linksMetadata Download high resolution version (1024x768, 282 KB) Summary Hexagonal basaltic stones at the Giants Causeway in Nothern Ireland co. ... Columnar jointed basalt in Turkey Columnar jointing in the basalt of the Giants Causeway in Ireland A joint is a generally planar fracture formed in a rock as a result of extensional stress. ... For other uses, see Giants Causeway (disambiguation). ... Northern Ireland (Irish: , Ulster Scots: Norlin Airlann) is a constituent country of the United Kingdom lying in the northeast of the island of Ireland, covering 5,459 square miles (14,139 km², about a sixth of the islands total area). ... Ukinrek Maars, Alaska; the result of a 10-day eruption in 1977. ...


Amygdaloidal structure is common in relict vesicles and beautifully crystallized species of zeolites, quartz or calcite are frequently found. In Geology, a vesicle is a small enclosed cavity found in some volcanic rock--such as basalt--formed by the entrapment of gas bubbles as the material solidifies. ... For other uses, see Crystal (disambiguation). ... Zeolite The micro-porous molecular structure of a zeolite, ZSM-5 Zeolites (Greek, zein, to boil; lithos, a stone) are minerals that have a micro-porous structure. ... For other uses, see Quartz (disambiguation). ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ...


Columnar basalt

During the cooling of a thick lava flow, contractional joints or fractures form. If a flow cools relatively rapidly, significant contraction forces build up. While a flow can shrink in the vertical dimension without fracturing, it cannot easily accommodate shrinking in the horizontal direction unless cracks form. The extensive fracture network that develops results in the formation of columns. The topology of the lateral shapes of these columns can broadly be classed as a random cellular network. These structures are often erroneously described as being predominantly hexagonal. In reality, the mean number of sides of all the columns in such a structure is indeed six (by geometrical definition), but polygons with three to twelve or more sides can be observed[3]. Note that the size of the columns depends loosely on the rate of cooling; very rapid cooling may result in very small (<1 cm diameter) columns, and vice versa. Columnar jointed basalt in Turkey Columnar jointing in the basalt of the Giants Causeway in Ireland A joint is a generally planar fracture formed in a rock as a result of extensional stress. ... Look up Contraction in Wiktionary, the free dictionary. ... This article is about mathematical mean. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ...


Perhaps the most famous basalt flow in the world is the Giant's Causeway on the northern coast of Ireland, in which the vertical joints form hexagonal columns and give the impression of having been artificially constructed. For other uses, see Giants Causeway (disambiguation). ... A regular hexagon A hexagon (also known as sexagon) is a polygon with six edges and six vertices. ...


An ancient 13th century religious complex, called Nan Madol, was built on the Pacific island of Pohnpei, using columnar basalt quarried from various locations on the island. The massive ruins remain to this day. Nan Madol Nan Madol, consisting of a series of small artificial islands linked by a network of canals, is often called the Venice of the Pacific. ... World Class Surf of Pohnpeis Palikir Pass a. ...

Columnar jointed basalt in Hong Kong - near Basalt Island and High Island Reservoir areas

For other uses, see Giants Causeway (disambiguation). ... The longer fragments of basalt at the base of the cliff can be larger than a person. ... Narooma is a town in the Australian state of New South Wales on the far south coast. ... Holyrood Park is a royal park in central Edinburgh, Scotland. ... Fingals Cave around 1900 View from West to East Staffa (Norse for staff, column, or pillar island), an island of the Inner Hebrides in Argyll and Bute, Scotland. ... Devils Tower is a monolith (more technically, an igneous intrusion) or volcanic neck located near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River. ... Official language(s) English Capital Cheyenne Largest city Cheyenne Area  Ranked 10th  - Total 97,818 sq mi (253,348 km²)  - Width 280 miles (450 km)  - Length 360 miles (580 km)  - % water 0. ... World Class Surf of Pohnpeis Palikir Pass a. ... Approaching Vík í Mýrdal The beach at Vík The village Vík in the south of Iceland is indicated on road signs from a long distance (about 180 km from Reykjavík), despite its small size (about 300 inhabitants). ...

Submarine eruptions

Pillow basalts on the south Pacific seafloor
Pillow basalts on the south Pacific seafloor

Image File history File links Pillow basalts on the south Pacific seafloor: Courtesy of NOAA. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Pillow basalts on the south Pacific seafloor: Courtesy of NOAA. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

Pillow basalts

When basalt erupts underwater or flows into the sea, the cold water quenches the surface and the lava forms a distinctive pillow shape, through which the hot lava breaks to form another pillow. This pillow texture is very common in underwater basaltic flows and is diagnostic of an underwater eruption environment when found in ancient rocks. Pillows typically consist of a fine-grained core with a glassy crust and have radial jointing. The size of individual pillows varies from 10 cm up to several metres.


When pahoehoe lava enters the sea it usually forms pillow basalts. However when a'a enters the ocean it forms a littoral cone, a small cone-shaped accumulation of tuffaceous debris formed when the blocky a'a lava enters the water and explodes from built-up steam.


The island of Surtsey in the Atlantic Ocean is a basalt volcano which breached the ocean surface in 1963. The initial phase of Surtsey's eruption was highly explosive, as the magma was quite wet, causing the rock to be blown apart by the boiling steam to form a tuff and cinder cone. This has subsequently moved to a typical pahoehoe type behaviour. Surtsey, sixteen days after the onset of the eruption Surtsey (Icelandic: Surturs island) is a volcanic island off the southern coast of Iceland. ...


Volcanic glass may be present, particularly as rinds on rapidly chilled surfaces of lava flows, and is commonly (but not exclusively) associated with underwater eruptions. Top stone is obsidian, below that is pumice and in lower right hand is rhyolite (light color) Obsidian is a type of naturally occurring glass, produced from volcanoes when the right kind of lava cools rapidly, e. ...


Life on basaltic rocks

The common corrosion features of underwater volcanic basalt suggest that microbial activity may play a significant role in the chemical exchange between basaltic rocks and seawater. The significant amounts of reduced iron, Fe(II), and manganese, Mn(II), present in basaltic rocks provide potential energy sources for bacteria. Recent research has shown that some Fe(II)-oxidizing bacteria cultured from iron-sulfide surfaces are also able to grow with basaltic rock as a source of Fe(II).[5] In recent work at Loihi Seamount, Fe- and Mn- oxidizing bacteria have been cultured from weathered basalts.[6] The impact of bacteria on altering the chemical composition of basaltic glass (and thus, the oceanic crust) and seawater suggest that these interactions may lead to an application of hydrothermal vents to the origin of life. Lōʻihi is a seamount and undersea volcano in the Hawaiian archipelago, located at 18. ... Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ... Hydrothermal vents are fissures in a planets surface from which geothermally heated water issues. ... For the definition, see Life. ...


Distribution

Paraná Traps, Brazil
Paraná Traps, Brazil

The lava flows of the Deccan Traps in India, the Paraná Traps in Brazil, the Siberian Traps in Russia, the Columbia River Plateau of Washington and Oregon, as well as parts of the California inner coastal ranges in the United States, as well as the Triassic lavas of eastern North America are basalts. Other famous accumulations of basalts include Iceland, the Karoo flood basalt province in South Africa and the islands of the Hawaii volcanic chain, forming above a mantle plume. Basalt is the rock most typical of large igneous provinces. Image File history File links Size of this preview: 800 × 558 pixel Image in higher resolution (1003 × 699 pixel, file size: 432 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Basalt ... Image File history File links Size of this preview: 800 × 558 pixel Image in higher resolution (1003 × 699 pixel, file size: 432 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Basalt ... Look up lava, Aa, pahoehoe in Wiktionary, the free dictionary. ... The Deccan Traps is a large igneous province located in west-central India and is one of the largest volcanic features on Earth. ... The Siberian Traps (Russian: ) form a large igneous province in Siberia. ... The Columbia River Plateau is shown in green on this map. ... For the capital city of the United States, see Washington, D.C.. For other uses, see Washington (disambiguation). ... This article is about the U.S. state. ... This article is about the U.S. state. ... The Triassic is a geologic period that extends from about 251 ± 0. ... North America North America is a continent [1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... The Karoo is a semi-desert region of South Africa. ... Moses Coulee showing multiple flood basalt flows of the Columbia River Basalt Group. ... This article is about the U.S. State. ... A lava lamp illustrates the basic concept of a mantle plume. ... Large Igneous provinces (LIPS) were originally defined by Coffin and Eldholm (1992) as areas of Earths surface that contain very large volumes of magmatic rocks (typically basalt but including rhyolites) erupted over extremely short geological time intervals of a few million years or less. ...


Ancient Precambrian basalts are usually only found in fold and thrust belts, and are often heavily metamorphosed. These are known as greenstone belts, because low-grade metamorphism of basalt produces chlorite, actinolite, epidote and other green minerals. The Precambrian (Pre-Cambrian) is an informal name for the supereon comprising the eons of the geologic timescale that came before the current Phanerozoic eon. ... This article is about zones of mixed sedimentary and volcanic rock sequences that often contain minable concentrations of gold, silver, copper, zinc and lead. ... Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i. ... Chlorite is a group of phyllosilicate minerals often classified as clays. ... Well-cleaved, dark, fine-grained chlorite-actinolite metadiabase intrudes light granitic gneiss Actinolite is an inosilicate mineral with the chemical formula Ca2(MgFe)5Si8O22(OH)2 // Mineralogy Actinolite is an intermediate member in a series between tremolite (Mg-rich) and ferro-actinolite (Fe-rich). ... Epidote from Slovakia Epidote is a calcium aluminium iron sorosilicate mineral, Ca2(Al, Fe)3(SiO4)3(OH), crystallizing in the monoclinic system. ...


Lunar and Martian basalt

The dark areas visible on Earth's moon, the lunar maria, are plains of flood basaltic lava flows. These rocks were sampled by the manned American Apollo program, the robotic Russian Luna program, and are represented among the lunar meteorites. This article is about Earths moon. ... Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... Moses Coulee showing multiple flood basalt flows of the Columbia River Basalt Group. ... This article is about the series of human spaceflight missions. ... The Luna programme was a series of 24 unmanned space missions sent to the Moon by the Soviet Union between 1959 and 1976. ... Lunar Meteorite Allan Hills 81005 A Lunar meteorite is a meteorite that is known to have originated on the Moon. ...


Lunar basalts differ from their terrestrial counterparts principally in their high iron contents, which typically range from about 17 to 22 wt% FeO. They also possess a stunning range of titanium concentrations (present in the mineral ilmenite), ranging from less than 1 wt% TiO2, to about 13 wt.%. Traditionally, lunar basalts have been classified according to their titanium content, with classes being named high-Ti, low-Ti, and very-low-Ti. Nevertheless, global geochemical maps of titanium obtained from the Clementine mission demonstrate that the lunar maria possess a continuum of titanium concentrations, and that the highest concentrations are the least abundant. Ilmenite is a weakly magnetic iron-black or steel-gray mineral found in metamorphic and igneous rocks. ... Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon...


Lunar basalts show exotic textures and mineralogy, particularly shock metamorphism, lack of the oxidation typical of terrestrial basalts, and a complete lack of hydration. While most of the Moon's basalts erupted between about 3 and 3.5 billion years ago, the oldest samples are 4.2 billion years old, and the youngest flows, based on the age dating method of "crater counting," are estimated to have erupted only 1.2 billion years ago. Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... Mineral hydration is an inorganic chemical reaction where water is added to the crystal structure of a mineral, usually creating a new mineral. ... Exploring Shorty crater during the Apollo 17 mission to the Moon. ...


Basalt is also a common rock on the surface of Mars, as determined by data sent back from the surface of Mars and by Martian meteorites. Adjectives: Martian Atmosphere Surface pressure: 0. ... A Martian meteorite is a meteorite that has landed on Earth but is believed to have originated from Mars. ...


Metamorphism

Basalts are important rocks within metamorphic belts, as they can provide vital information on the conditions of metamorphism within the belt. Various metamorphic facies are named after the mineral assemblages and rock types formed by subjecting basalts to the temperatures and pressures of the metamorphic event. These are; The term Metamorphic can be associated with a number of meanings:- Metamorphic rock The term for rocks that have been transformed by extreme heat and pressure. ... The term facies was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy (see Cross and Homewood 1997), which replaced the earlier notions of Neptunism. ...

Metamorphosed basalts are important hosts for a variety of hydrothermal ore deposits, including gold deposits, copper deposits, volcanogenic massive sulfide ore deposits and others. Greenschist is a general field petrologic term applied to metamorphically altered mafic volcanic rock. ... Blueschist is a rock that forms by the metamorphism of sodium-rich basic rocks at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 400 degrees Celsius (cool by metamorphic standards). ... Zeolite The micro-porous molecular structure of a zeolite, ZSM-5 Zeolites (Greek, zein, to boil; lithos, a stone) are minerals that have a micro-porous structure. ... Modern petrology defnes a granulite sensuo stricto as a coarse grained, high-grade metamorphic rock composed primarily of pyroxene, plagioclase feldspar and accessory garnet, oxide and amphibole. ... Eclogite is a coarse-grained, mafic-to-ultramafic grouping of metamorphic rocks of special interest on account of the variety of minerals they contain and their microscopic structures and geological relationships. ... Hydrothermal circulation in the oceans is the passage of the water through mid-ocean Ridge (MOR) systems. ... For other uses, see Ore (disambiguation). ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... For other uses, see Copper (disambiguation). ... Volcanogenic massive sulfide ore deposits or VMS are a type of metal sulfide ore deposit, mainly Cu-Zn, associated with certain types of volcanism. ...


See also

Wikimedia Commons has media related to:
Basalt

Image File history File links Commons-logo. ... Basalt fiber or fibre is a material made from extremely fine fibers of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Moses Coulee showing multiple flood basalt flows of the Columbia River Basalt Group. ...

References

  1. ^ See the PETDB database.Hyndman, Donald W. (1985). Petrology of igneous and metamorphic rocks, 2nd ed., McGraw-Hill. ISBN 0-07-031658-9. 
  2. ^ Blatt, Harvey and Robert Tracy (1996). Petrology, 2nd ed., Freeman. ISBN 0-7167-2438-3. 
  3. ^ D. Weaire and N. Rivier. Contemporary Physics 25 1 (1984), pp. 55–99
  4. ^ http://www.pohnpeiheaven.com/pwisehn_malek.htm Alex Zuccarelli, 2003, Pohnpei-Between Time & Tide . Pwisehn Malek
  5. ^ Katrina J. Edwards, Wolfgang Bach and Daniel R. Rogers, Geomicrobiology of the Ocean Crust: A Role for Chemoautotrophic Fe-Bacteria, Biol. Bull. 204: 180-185. (April 2003) http://www.biolbull.org/cgi/content/full/204/2/180
  6. ^ Templeton, A.S., Staudigel, H., Tebo, B.M. (2005). Diverse Mn(II)-oxidizing bacteria isolated from submarine basalts at Loihi Seamount, Geomicrobiology Journal, v. 22, 129-137. http://www.ebs.ogi.edu/tebob/pdfs/Templeton%20GeomicroJ.pdf
  • A. Y. Ozerov, The evolution of high-alumina basalts of the Klyuchevskoy volcano, Kamchatka, Russia, based on microprobe analyses of mineral inclusions. Journal of Volcanology and Geothermal Research, v. 95, p. 65-79 (2000).
  • A. W. Hofmann, Sampling mantle heterogeneity through oceanic basalts: isotopes and trace elements. Treatise on Geochemistry Volume 2, pages 61-101 Elsevier Ltd. (2003). ISBN 0-08-044337-0 In March, 2007, the article was available on the web at http://www1.mpch-mainz.mpg.de/~geo/hofmann/Hofmann.mantle_heterogen1.pdf.
  • A. V. Sobolev and others, The amount of recycled crust in sources of mantle-derived melts. Science, v. 316, p. 412-417 (2007). http://www.sciencemag.org/cgi/content/abstract/316/5823/412

External links

  • Lava - water interface
  • Pillow lava USGS
  • Petrology of Lunar Rocks and Mare Basalts
  • Basalt in Northern Ireland
  • Basalt Columns

  Results from FactBites:
 
USGS Photo Glossary: Basalt (0 words)
Basalt is erupted at temperatures between 1100 to 1250° C. More about volcanic and plutonic rocks.
Basalt is the most common rock type in the Earth's crust (the outer 10 to 50 km).
Basaltic magma is commonly produced by direct melting of the Earth's mantle, the region of the Earth below the outer crust.
Basalt - LoveToKnow 1911 (1208 words)
Olivine and augite are the commonest porphyritic minerals in basalts, the former green or yellowish (and weathering to green or brown serpentine), the latter pitch-fl.
Basaltic lavas are frequently spongy or pumiceous, especially near their surfaces; and, in course of time, the steam cavities become filled with secondary minerals such as calcite, chlorite and zeolites.
In the vitreous basalts sometimes very few crystallized minerals are observable; the greater part of the rock is a dark brown glassy material, almost opaque even in the thinnest sections, and generally charged with fl grains of magnetite, skeleton crystals of augite or felspar, spherulites, perlitic cracks, cmsteam vesicles.
  More results at FactBites »

 
 

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