01:460:101 Lecture Notes - Lecture 5: Partial Melting, Kyanite, Metamorphic Facies
28 Sep 2016
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Document Summary
Factors of metamorphic rock characteristics: texture and mineral content depend on . Parent rock composition: temperature and pressure during metamorphism, effects of tectonic forces, effects of fluids such as water. Usually no new material other than water is added during metamorphism. Resulting metamorphic rock will have similar composition to parent rock: temperature. Heat for metamorphism come from earth"s deep interior. All minerals stable over certain temperature range. If range is exceeded new minerals form. If temperature gets high enough, melting will occur. Lithostatic or confining pressure applied equally in all directions. Pressure proportional to depth within the earth. Directed pressure- plate boundaries, folding and faulting. High-pressure minerals more compact/more dense: tectonic forces. Often lead to forces that are not equal in all directions (differential stress) Compressive stress causes flattening perpendicular to stress. Shearing causes flattening by sliding parallel to stress. Planar rock texture of aligned minerals produced by differential stress is known as foliation.
