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In metamorphic geology, a compatibility diagram shows how the mineral assemblage of a metamorphic rock in thermodynamic equilibrium varies with composition at a fixed temperature and pressure. Compatibility diagrams provide an excellent way to analyze how variations in the rock's composition affect the mineral paragenesis that develops in a ...
Triangular diagrams showing the aluminium (A), calcium (C) and iron (F) content of the main phases (dark dots) in metamorphic rocks in various facies. Thin grey lines are stable phase equilibria. Triangular diagrams showing the aluminium (A), iron (F) and magnesium (M) content of the main phases (dark dots and, when the composition can vary ...
Figure 1. Petrogenetic grid for metapelites (several authors). [1] [2] Metamorphic facies included are: BS = Blueschist facies, EC = Eclogite facies, PP = Prehnite-Pumpellyite facies, GS = Granulite facies, EA = Epidote-Amphibolite facies, AM = Amphibolite facies, GRA = Granulite facies, UHT = Ultra-High Temperature facies, HAE = Hornfels-Albite-Epidote facies, Hbl = Hornblende-Hornfels facies ...
A petrogenetic grid is a geologic phase diagram that plots experimentally derived metamorphic reactions at their pressure and temperature conditions for a given rock composition. This allows metamorphic petrologists to determine the pressure and temperature conditions under which rocks metamorphose.
A generic phase diagram with unspecified axes; the invariant point is marked in red, metastable extensions labeled in blue, relevant reactions noted on stable ends of univariant lines. This rule is geometrically sound in the construction of phase diagrams since for every metastable reaction, there must be a phase that is relatively stable. This ...
Igneous and metamorphic petrology are commonly taught together because both make heavy use of chemistry, chemical methods, and phase diagrams. Sedimentary petrology is commonly taught together with stratigraphy because it deals with the processes that form sedimentary rock . [ 3 ]
In petrology, metamorphic phases can be distinguished by analysis of minerals and microstructures (petrography) in metamorphic rocks.By analysing the sequence in which the minerals and structures were formed, more than one phase can be found in most metamorphic rocks (this is called polymetamorphism).
Dynamic recrystallization occurs when a rock undergoes metamorphic conditions and reequilibrium of a minerals chemical composition. [1] This happens when there is a decrease in free energy stored in deformed grains. Deformed micas can store a sufficient amount of strain energy that can allow recrystallization to occur.