intro_to_geo_15

intro_to_geo_15 - Metamorphism cont. Types of metamorphic...

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Metamorphism cont. Types of metamorphic rocks Nonfoliated metamorphic rocks include (quartzite, marble) These have no preferred planar fabric Foliated metamorphic rocks include slate, phyllite, schist, gneiss These have a preferred orientation of minerals or aggregate of minerals Metamorphic grade Metamorphic grade is usually assessed on the basis of the mineral assemblage making up the metamorphic rock, as well as its foliation and other textural clues (such as grain size) Facies is a more precise term used for a restricted range of temperatures and pressures, defined by the presence of key minerals Metamorphic facies Temperature-pressure fields are termed metamorphic facies Facies are diagnosed from rocks using index minerals and mineral assemblages High-grade rocks are formed at high temperatures (and pressures) Low-grade rocks are produced at lower temperatures (and pressures) Metamorphic grade vs. facies A metamorphic grade refers to a series of temperature and (to a less extent)
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This note was uploaded on 04/08/2011 for the course GEOL 2001 taught by Professor Babaie during the Winter '09 term at UGA.

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intro_to_geo_15 - Metamorphism cont. Types of metamorphic...

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