Sedimentary Rocks: Review

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Sedimentary Rocks Review
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Metamorphic Rocks

• Dr. David Steer

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Rock Cycle
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Metamorphic Rocks

• Change in composition and/or texture of a rock
• Occurs as the result of increasing pressure
  and/or temperature.

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Regional Metamorphism

• Regional metamorphism occurs when rocks undergo
  increased temperatures and pressures
• Associated with the formation of mountain belts.
• Rocks may be buried to great depths (10-20 km)
• Temperatures in excess of 700 oC and pressures of
  7 kilobars (7 million atmospheres).
• Increase in grain size
• Platy minerals become aligned (foliated)
• At high enough grades segregation of light and
  dark minerals occur (gneiss)

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Regional Metamorphism

• Draw a schematic picture of the process

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Examples of Regional Metamorphic Rocks

• Schist
• Forms when mudrocks are heated

• Gneiss
• Forms when rocks ranging from mudrocks to
  granites are heated and pressurized

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Contact Metamorphism

• Contact metamorphism occurs when rocks come in
  contact with a heat source (usually a magma
  body).
• Essentially the rocks are getting baked, like in
  an oven.
• Grain size increases as the result of increased
  temperature.
• Grains are often randomly oriented

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Contact Metamorphism

• Draw a schematic picture of the process

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Review

• Two of these rocks are igneous, 2 are metamorphic
  and one is sedimentary. Which rocks most likely
  metamorphic?

Temperature
A
B
C
Depth
E
D
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Examples of contact metamorphic Rocks

• Marble
• forms when limestone is heated

• Quartzite
• forms when sandstone is heated

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Create a Concept Map
Key Words regional metamorphism gneiss magma
chambers contact metamorphism heat heat and
pressure mountain belts grain size marble non-foli
ated rocks
Linking phrases surrounding can be formed
by classified by caused by increasing that
results in such as formed from an existing rock
like associated with
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Identify your metamorphic rocks