fugacity magmas enstatite pyroxene cumulate crystallizes plagioclase forsterite olivine crystallization crystallize epitaxy petrogenesis liquidus magmatic magma verneuil recrystallization crystallisation feldspar igneous melts fractional ultramafic chromite mgo silicate siliceous textures granitic
which of the following is not one of the processes by which crystals separate from a magma
Fractional crystallization ( geology ) - wikipedia Fractional crystallization ( geology ) One of the main processes of magmatic differentiation This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . ( September 2014 ) ( Learn how and when to remove this template message ) <Th_colspan="2"> Crystallization <Td_colspan="2"> <Th_colspan="2"> Concepts <Td_colspan="2"> Crystallization Crystal growth Recrystallization Seed crystal Protocrystalline Single crystal <Th_colspan="2"> Methods and technology <Td_colspan="2"> Boules Bridgman -- Stockbarger technique Crystal bar process Czochralski process Epitaxy Flux method Fractional crystallization Fractional freezing Hydrothermal synthesis Kyropoulos process Laser - heated pedestal growth Micro-pulling - down Shaping processes in crystal growth Skull crucible Verneuil process Zone melting <Th_colspan="2"> Fundamentals <Td_colspan="2"> Nucleation Crystal Crystal structure Solid <Td_colspan="2"> Schematic diagrams showing the principles behind fractional crystallisation in a magma . While cooling , the magma evolves in composition because different minerals crystallize from the melt . 1 : olivine crystallizes ; 2 : olivine and pyroxene crystallize ; 3 : pyroxene and plagioclase crystallize ; 4 : plagioclase crystallizes . At the bottom of the magma reservoir , a cumulate rock forms . Fractional crystallization , or crystal fractionation , is one of the most important geochemical and physical processes operating within the Earth 's crust and mantle . It is one of the main processes of magmatic differentiation . Fractional crystallization is the removal and segregation from a melt of mineral precipitates ; except in special cases , removal of the crystals changes the composition of the magma . In essence , fractional crystallization is the removal of early formed crystals from an originally homogeneous magma ( for example , by gravity settling ) so that these crystals are prevented from further reaction with the residual melt . The composition of the remaining melt becomes relatively depleted in some components and enriched in others , resulting in the precipitation of a sequence of different minerals . Fractional crystallization in silicate melts ( magmas ) is complex compared to crystallization in chemical systems at constant pressure and composition , because changes in pressure and composition can have dramatic effects on magma evolution . Addition and loss of water , carbon dioxide , hydrogen , and oxygen are among the compositional changes that must be considered . For example , the partial pressure ( fugacity ) of water in silicate melts can be of prime importance , as in near - solidus crystallization of magmas of granite composition . The crystallization sequence of oxide minerals such as magnetite and ulvospinel is sensitive to the oxygen fugacity of melts , and separation of the oxide phases can be an important control of silica concentration in the evolving magma , and may be important in andesite genesis . Experiments have provided many examples of the complexities that control which mineral is crystallized first as the melt cools down past the liquidus . One example concerns crystallization of melts that form mafic and ultramafic rocks . MgO and SiO concentrations in melts are among the variables that determine whether forsterite olivine or enstatite pyroxene is precipitated , but the water content and pressure are also important . In some compositions , at high pressures without water crystallization of enstatite is favored , but in the presence of water at high pressures , olivine is favored . Granitic magmas provide additional examples of how melts of generally similar composition and temperature , but at different pressure , may crystallize different minerals . Pressure determines the maximum water content of a magma of granite composition . High - temperature fractional crystallization of relatively water - poor granite magmas may produce single - alkali - feldspar granite , and lower - temperature crystallization of relatively water - rich magma may produce two - feldspar granite . During the process of fractional crystallization , melts become enriched in incompatible elements . Hence , knowledge of the crystallization sequence is critical in understanding how melt compositions evolve . Textures of rocks provide insights , as documented in the early 1900s by Bowen 's reaction series . An example of such texture , related to fractioned crystallization , is intergranular ( also known as intercumulus ) textures that develop wherever a mineral crystallizes later than the surrounding matrix , hence filling the left - over interstitial space . A variety of Cr , Fe , and Ti oxides show such textures , like intergranular chromite in a siliceous matrix . Experimentally - determined phase diagrams for simple mixtures provide insights into general principles . Numerical calculations with special software have become increasingly able to simulate natural processes accurately . See also ( edit ) Cumulate rock Flow banding -- Bands or layers that can sometimes be seen in rock that formed from magma Fractional crystallization ( chemistry ) Igneous differentiation -- Processes by which magmas undergo bulk chemical change during the partial melting process , cooling , emplacement , or eruption Layered intrusion References ( edit ) Jump up ^ Oxford University Press 1999 Jump up ^ Wilson B.M. ( 1989 ) . Igneous Petrogenesis A Global Tectonic Approach . Springer . p. 82 . ISBN 9780412533105 . Jump up ^ Oxford University Press 1999 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Fractional_crystallization_(geology)&oldid=864370509 '' Categories : Igneous rocks Igneous petrology Hidden categories : Articles with short description Articles needing additional references from September 2014 All articles needing additional references Wikipedia articles needing factual verification from December 2017 Talk About Wikipedia Azərbaycanca Deutsch Eesti Español Français עברית Nederlands Português Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Tiếng Việt 6 more Edit links This page was last edited on 16 October 2018 , at 19 : 33 ( UTC ) . Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply . By using this site , you agree to the Terms of Use and Privacy Policy . Wikipedia ® is a registered trademark of the Wikimedia Foundation , Inc. , a non-profit organization . About Wikipedia