Change of minerals in pre-existing rocks without melting into liquid magma
For other uses, see Metamorphism (disambiguation).
Schematic representation of a metamorphic reaction. Abbreviations of minerals: act = actinolite; chl = chlorite; ep = epidote; gt = garnet; hbl = hornblende; plag = plagioclase. Two minerals represented in the figure do not participate in the reaction, they can be quartz and K-feldspar. This reaction takes place in nature when a mafic rock goes from amphibolite facies to greenschist facies.A cross-polarized thin section image of a garnet-mica-schist from Salangen, Norway showing the strong strain fabric of schists. The black crystal is garnet, the pink-orange-yellow colored strands are muscovite mica, and the brown crystals are biotite mica. The grey and white crystals are quartz and (limited) feldspar.
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of 150 °C (300 °F), and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation.[1] Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface.[2]
Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as prograde metamorphism, while decreasing temperature and pressure characterize retrograde metamorphism.
Metamorphic petrology is the study of metamorphism. Metamorphic petrologists rely heavily on statistical mechanics and experimental petrology to understand metamorphic processes.
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place...
Shock metamorphism or impact metamorphism describes the effects of shock-wave related deformation and heating during impact events. The formation of similar...
"The Metamorph" is the first episode of the second series of Space: 1999 (and the twenty-fifth overall episode of the programme). The screenplay was written...
processes that help bring about metamorphism. However, metamorphism can take place without metasomatism (isochemical metamorphism) or at depths of just a few...
temperature conditions which produce this type of metamorphism. List of minerals List of rock types Metamorphism "Blueschist". About.com Education. Archived...
during regional metamorphism accompanying the process of mountain building (orogeny) and usually reflects a medium grade of metamorphism. Schist can form...
classical metamorphism which is the in-situ mineralogical change of a rock without appreciable change in the chemistry of the rock. Because metamorphism usually...
or chemically to form a different rock, called metamorphic. Regional metamorphism refers to the effects on large masses of rocks over a wide area, typically...
subjection of the protolith (the original rock material that undergoes metamorphism) to extreme shearing force, a sliding force similar to the pushing of...
metamorphism at low thermal gradients of <10 °C/km, and the other is amphibolite to granulite facies series that was produced by rifting metamorphism...
Hemimetabolism or hemimetaboly, also called partial metamorphosis and paurometabolism, is the mode of development of certain insects that includes three...
these minerals to form. Buchan metamorphism has the facies series greenschist-amphibolite-granulite Barrovian metamorphism has the same facies series but...
reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to tectonic compression within orogenic belts. Sandstones...
Amphibolite frequently forms by metamorphism of mafic igneous rocks, such as basalt. However, because metamorphism creates minerals entirely based upon...
Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite. Metamorphism causes variable recrystallization...
regional metamorphism at depth. By contrast, the metamorphic zones surrounding the Fanad pluton of Ireland, which formed by contact metamorphism at a shallower...
metamorphosed. These are known as greenstone belts, because low-grade metamorphism of basalt produces chlorite, actinolite, epidote and other green minerals...
is subjected to the great heat and pressure associated with regional metamorphism, the individual quartz grains recrystallize along with the former cementing...
form under extreme temperature and pressure conditions during prograde metamorphism, when partial melting occurs in metamorphic paleosome. Components exsolved...
silicate-carbonate metamorphism. However, evidence from thermodynamic modeling has shown that the pressures and temperatures necessary for this type of metamorphism are...
northern Gondwana over-riding southern Gondwana and was accompanied by metamorphism and the intrusion of granites. Subduction zones, active since the Neoproterozoic...
experience a transition from early metamorphism—which forms hornfels, reaction skarns, and skarnoids—to late metamorphism, which forms relatively coarser...
sillimanite Buchan metamorphism occurs often in extensional settings, for example at rift basins. In contact metamorphism (metamorphism caused by high temperatures...
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