Metamorphic Rocks

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Metamorphic Rocks
A Rock Group in action

• Classified according to the arrangement of the
  grains that make up the rocks the minerals in
  them

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Metamorphic rocks are nicknamedChanging Rocks.
Why?
They are made from other rocks
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How do Metamorphic rocks form?

• From heat pressure deep inside Earth

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Regional Metamorphism Metamorphic rocks can form
from Igneous, Sedimentary, or other Metamorphic
rocks as they are pushed down toward the heat of
the mantle.
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Metamorphic Rocks Contact Metamorphism
Contacting hot magma can change the surrounding
rocks
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Formation of Metamorphic Rocks

•  
• Stage 1 Mineral Alignment
•  
• Pressure
• Heat
•  

-Original parent rock with minerals in rock
structure. (X,Y,Z).  - Rock is subject to low
grade pressure temperatures then the minerals
are flattened. 
x
z
Y
x
z
Y
z
Y
x
z
z
z
x
x
x
Y
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• Stage 2 Banding
• "Recrystallization"
• extreme heat pressure allows individual
  crystals to
• - Grow larger
• Consolidate together
• Separate according to density differences. 

x
x
x
x
x
x
x
z
x
z
x
x
x
z
z
z
z
x
z
z
z
z
z
z
z
x
z
z
z
Y
Y
x
x
Y
Y
Y
z
Y
Y
Y
z
Y
Y
Y
Y
Y
Y
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2 Types of Metamorphic Rock

• Foliated

• Nonfoliated

Banded
Nonbanded
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Foliated Metamorphic Rock

• Definition Grains arranged in layers or bands
  that split into layers
• Examples
• Slate Schist Gneiss

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Original Rock ?New Metamorphic Rock

• Shale ??????

• Slate

Shale (sedimentary) changes to Slate when heated
squeezed by pressure.
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Original Rock ? New Metamorphic Rock

• Granite ??????Gneiss

Granite (Igneous) changes to Gneiss when heated
squeezed by pressure.
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Nonfoliated Metamorphic Rock

• Definition Mineral grains arranged randomly, do
  not split into layers
• Examples
• Marble Quartzite

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Original Rock ? New Metamorphic Rock

• Sandstone ??????Quartzite

When Sandstone (Sedimentary) is under extreme
heat pressure, Quartzite will form.
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Identification of Metamorphic Rocks
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Metamorphism Scale
Increasing Depth, Pressure Temperature
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Uses of Metamorphic Rocks

• Slate
• Marble

• Old fashioned chalkboards, roofs, walkways, trim
  on buildings
• Sculptures (most famous
• Lincoln Memorial in Washington
• D.C.)
• Buildings

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How are the 3 rock types related?