Rocks The Geologic Dictionary

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Rocks The Geologic Dictionary
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Metamorphic Rocks

• Rocks Under Stress

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Metamorphism

• Recrystalization
• Solid-State Chemical Reactions
• No Melting

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Factors that affect Metamorphism

• Parent Rock Composition
• Temperature
• Pressure
• Fluids

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Factors that affect Metamorphism

• Parent Rock Composition
• Temperature
• Pressure
• Fluids

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Factors that affect Metamorphism
Lithostatic pressure

• Parent Rock Composition
• Temperature
• Pressure
• Fluids

Directional Pressure
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Directed Pressure Results in
Foliation
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Foliation Under a Microscope
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Metamorphic Grade
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Factors that affect Metamorphism

• Parent Rock Composition
• Temperature
• Pressure
• Fluids

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Metamorphic Rocks - Identification
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Metamorphic Textures(All Crystalline)
Nonfoliated
Foliated
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Foliation
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Composition - Index Minerals
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Composition - Index Minerals
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Mineral Composition - Geothermometers
Rock Forms 500-550C
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Foliated Metamorphic Rocks
Parent Rock - Shale
Slate (Low Grade)
Schist (Medium Grade)
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Foliated Rocks (cont.)
Felsic Parent Rock
Gneiss (High Grade)
Migmatite (Very High Grade)
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NonFoliated Rocks
Parent RockLimestone
Marble(Low to High Grade)
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Nonfoliated Rocks (cont.)
Parent Rocks
Quartzite
Sandstone
Metacoglomerate
Conglomerate
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Metamorphic Rocks - Interpretation
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Metamorphic EnvironmentsMetamorphic Facies
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Metamorphic Rock Translations

• Chemical Composition
• Mineral Composition
• Foliation

• Parent Rock (Protolith)
• T P of Formation(Depth / Facies)
• T P of Formation (Depth / Facies)