Term
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Definition
PHANERITIC
Large, visible Xls
Cools very slowly
Forms underground |
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Term
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Definition
PEGMATIC
Extremely lg xls =>2cm
Cools very slowly
Forms underground |
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Term
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Definition
APHANITIC
Very fine grained
Cools rapidly
Forms near the surface |
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Term
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Definition
PORPHYRITIC
Large xls surrounded by a finer grained groundmass (matrix)
Cools slow at first then fast
Begins forming underground and finishes on Earth's surface |
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Term
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Definition
PYROCLASTIC
When a piece of rox is ripped from the chamber walls but doesn't combine w/the melt.
Cools rapidly
Forms underground |
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