Igneous Activity II

1
Igneous Activity II

• Magma

2
Magma

• Making magma rocks melts more easily with
• Increasing temperature
• Decreasing pressure
• Addition of water

3
Magma

• Environments of magma formation
• Spreading centers
• Hot asthenosphere oozes into spreading ridge
• Mantle plume
• Hot plume, buoyant relative to surroundings
• Subduction zones
• Addition of water
• Frictional heating

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World distribution of volcanoes
5
Subduction Zone Igneous Activity
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Volcanism of the Pacific Northwest
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Mt. Hood
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Hot Spot Volcanism
9
Hawaii Hotspot under oceanic crust
10
Yellowstone Hotspot under continental crust
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Caldera in Yellowstone NP
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Spreading Center Volcanism