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Encyclopedia > Xenolith
A xenolith

A xenolith (Greek: 'foreign rock') is a rock fragment which becomes enveloped in a larger rock during the latter's development and hardening. In geology, the term xenolith is almost exclusively used to describe inclusions in igneous rock during magma emplacement and eruption. Xenoliths may be engulfed along the margins of a magma chamber, torn loose from the walls of an erupting lava conduit or explosive diatreme or picked up along the base of a flowing lava on Earth's surface. A xenocryst is an individual foreign crystal included within an igneous body. Examples of xenocrysts are quartz crystals in a silica-deficient lava and diamonds within kimberlite diatremes. A xenolith (public domain from [1]) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... A xenolith (public domain from [1]) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... The rocky side of a mountain creek near Orosí, Costa Rica. ... This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ... Volcanic rock on North America Plutonic rock on North America Igneous rocks form when 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. ... Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ... Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ... Look up lava, Aa, pahoehoe in Wiktionary, the free dictionary. ... A Diatreme is a volcanic pipe or feature formed by a gas or volatile rich explosive magma. ... Quartz is one of the most common minerals in the Earths continental crust. ... This article is about the gemstone. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ... A Diatreme is a volcanic pipe or feature formed by a gas or volatile rich explosive magma. ...


Although the term xenolith is most commonly associated with igneous inclusions, a broad definition could include rock fragments which have become encased in sedimentary rock. Xenoliths are sometimes found in recovered meteorites. Two types of sedimentary rock: limey shale overlaid by limestone. ... Willamette Meteorite A meteorite is a natural object originating in outer space that survives an impact with the Earths surface without being destroyed. ...

A xenolith in Larchmont, New York
A xenolith in Larchmont, New York

To be considered a true xenolith, the included rock must be identifiably different from the rock in which it is enveloped; an included rock of similar type is called an autolith or a cognate inclusion. Image File history File linksMetadata Download high-resolution version (1520x2272, 2114 KB) A xenolith in Larchmont, New York Photo made by Chris Bolger (Curvedpitch1) from en. ... Image File history File linksMetadata Download high-resolution version (1520x2272, 2114 KB) A xenolith in Larchmont, New York Photo made by Chris Bolger (Curvedpitch1) from en. ...


Xenoliths and xenocrysts provide important information about the composition of the otherwise innacessible mantle. Basalts, kimberlites, lamproites and lamprophyres, which have their source in the upper mantle, often contain fragments and crystals assumed to be a part of the originating mantle mineralogy. Xenoliths of dunite, peridotite and spinel lherzolite in basaltic lava flows are one example. Kimberlites contain, in addition to diamond xenocrysts, fragments of lherzolites of varying composition. The aluminium-bearing minerals of these fragments provide clues to the depth of origin. Calcic plagioclase is stable to 25 km depth. Between 25 km and about 60 km, spinel is the stable aluminium phase. At depths greater than about 60 km, dense garnet becomes the aluminium-bearing mineral. Some kimberlites contain xenoliths of eclogite, which is considered to be the high-pressure metamorphic product of oceanic basaltic crust, as it descends into the mantle along subduction zones. (Blatt, 1996) Earth cutaway from core to exosphere. ... Basalt Basalt (IPA: ) is a common gray to black extrusive volcanic rock. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ... Lamproite is a peralkaline volcanic rock. ... Lamprophyres (Greek Lampros, bright, and the terminal part of the word porphyry, meaning rocks containing bright porphyritic crystals) are a group of rocks containing phenocrysts, usually of biotite and hornblende (with bright cleavage surfaces), often also of olivine and augite, but not of feldspar. ... Dunite is an igneous, plutonic rock, of ultramafic composition, with coarse grained or phaneritic texture. ... Peridotite xenolith from San Carlos, southwestern United States. ... The spinels are any of a class of minerals which crystallize in the isometric system with an octahedral habit. ... Lherzolite is a type of ultramafic igneous rock. ... Basalt Basalt (IPA: ) is a common gray to black extrusive volcanic rock. ... Lherzolite is a type of ultramafic igneous rock. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Standard atomic weight 26. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... The spinels are any of a class of minerals which crystallize in the isometric system with an octahedral habit. ... Garnet is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Standard atomic weight 26. ... 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. ... Categories: Geology stubs | Plate tectonics ...


References

Wikimedia Commons has media related to:
Xenoliths
  • Blatt, Harvey, and Robert J. Tracy (1996) Petrology, W. H. Freeman, 2nd ed. ISBN 0-7167-2438-3

  Results from FactBites:
 
Xenolith Summary (750 words)
A xenolith is a rock fragment embedded in, and distinct in texture and composition from, a surrounding mass of igneous rock.
Xenoliths may be captured by magma near the surface or deep in the mantle.
Xenoliths may be engulfed along the margins of a magma chamber, torn loose from the walls of an erupting lava conduit or explosive diatreme, or picked up along the base of a flowing lava on Earth's surface.
A xenolith Greek foreign rock is a rock... (161 words)
A "xenolith" (Greek: "foreign rock") is a rock which becomes enveloped in a larger rock during the latter's development and hardening.
In geology, the term "xenolith" is almost exclusively used to describe inclusions in igneous rock during its formation and cooling process, but a broad definition could include rock fragments which have become encased in sedimentary rock.
To be considered a true xenolith, the included rock must be identifiably different from the rock in which it is enveloped; an included rock of similar type is called an "autolith".
  More results at FactBites »

 
 

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