Metamorphic Rocks

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Metamorphic Rocks

• Mr. DeMarco

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Metamorphic Rocks

• Rocks which are formed from other rocks (all
  three types) within Earths crust.
• Formed by great pressures (usually from the
  sedimentary rock layers above) and heat (from
  internal heat below).
• Formed by recrystallization rearrangement of
  crystals in rock.
• Compression makes these rocks dense.

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Texture/Structure(based on texture and mineral
composition)

• FOLIATION
• Forms in specific sheets or layers
• Example Slate, Schist
• Some rocks show GNEISSIC BANDING which is an
  alternation of light and dark layers in a rock.
• Example Gneiss
• Hey Mr. DeMarco, you sure are Gneiss.
• This would mean that I have light and dark
  layers
• Ill take it as a compliment.

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Texture/Structure(continued)

• Some of the foliated rocks have a DISTORTED
  STRUCTURE curving or folding of the bands
  (layers) of minerals.

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Texture/Structure(continued)

• NONFOLIATED
• Layers (banding) does not exist.
• Can see a conglomerate of crystals.
• Example Marble, Quartzite

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CONTACT METAMORPHISM

• Metamorphic rocks can form at the boundary of an
  IGNEOUS INTRUSION (heat) and the sedimentary
  layers that it cuts through (pressure).
• There is blending of one rock type into another
  in this transition zone.

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Regional Metamorphism

• Metamorphism over a large geographic region due
  to a large heat source below Earths surface.

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FROM THE ESRT