3.4 Metamorphic Rocks

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3.4 Metamorphic Rocks

• Metamorphism to change form
• I. Formation of Metamorphic Rocks
• - Most changes occur at high temperatures and
  pressures a few km below the Earths surface.

Gneiss Rock
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• Contact Metamorphism
• hot magma moves into rock.
• B. Regional Metamorphism
• results in large-scale
• deformation and high-grade
• metamorphism.

Important Vocab!
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II. Agents of Metamorphism

• A. Heat The most important agent.
• Provides the energy needed to drive
  
• chemical reactions.
• - The heat comes from magma and the change in
  temperature with depth.
• B. Pressure (Stress)
• Causes a more compact
• rock with greater density

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Origin of Pressure in Metamorphism
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III. Classification of Metamorphic Rocks

• Can be classified by texture and composition.
• Foliated Metamorphic Rocks - rock
• has a layered or banded appearance.
• Ex Gneiss Schist.

Important Vocab!
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Gneiss Typically Displays a Banded Appearance
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Important Vocab!

• B. Nonfoliated Metamorphic Rocks
• - Does not have a banded texture.
• - Most only contain one mineral.
• Ex Marble (calcite)
• parent rock limestone Quartzite
• Marble

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Marble - A Nonfoliated Metamorphic Rock
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ESRT pg 7
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