1. Sedimentary Rocks: Review

2. Metamorphic Rocks
Dr. David Steer

3. Rock Cycle

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

5. 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)

6. Regional Metamorphism
Draw a schematic picture of the process

7. Examples of Regional Metamorphic Rocks
Schist
Forms when mudrocks are heated
Gneiss
Forms when rocks ranging from mudrocks to granites are heated and pressurized

8. 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

9. Contact Metamorphism
Draw a schematic picture of the process

10. 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

11. Examples of contact metamorphic Rocks
Marble
forms when limestone is heated
Quartzite
forms when sandstone is heated

12. Create a Concept Map Key Words: Linking phrases: regional metamorphism
gneiss
magma chambers
contact metamorphism
heat
heat and pressure
mountain belts
grain size
marble
non-foliated 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

13. Identify your metamorphic rocks