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14 Cards in this Set
- Front
- Back
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What do we use to classify igneous rocks? |
Texture and colour |
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What are the 4 compositions of igneous rocks? |
Felsic, intermediate, magic, and ultra mafic |
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What are the different types of textures for igneous rocks? |
Phaneritic, aphanitic, glassy, porphyritic, pyroclastic, pegmatitic, vesicular |
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How does phaneritic texture (coarse-grained) rocks occur? |
Magma intrusions cool slowly, forming large mineral grains |
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How is aphanitic texture formed? |
Rocks formed by cooling lava are fine grained; cools rapidly |
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How is glassy texture formed? (No minerals) |
Very rapid cooling (quench) or flow of very silica-rich lava may produce volcanic glass (no mineral grains) |
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How is porphyritic texture formed? |
Partial crystallization in a magma chamber (minerals and melt) --> magma and crystals erupt at the surface --> remaining melt will cool quickly |
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How are pyroclastic textures formed? |
Violent Volcanic eruptions |
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How are pegmatitic textures formed? |
Crystallize from water-rich magma a which enhances crystallization |
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How is vesicular texture formed? |
Voids left by gas bubbles |
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What is the largest source of magma? |
Upper mantle |
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How do you generate magma from solid rock? |
Increase temperature, decrease in pressure, addition of volatiles |
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Is the mantle static or dynamic? |
Dynamic |
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How do magmas evolve? |
Magmatic differtiation, assimilation, magma mixing |
