1. Earth Science Chapter 3 Section 4
Metamorphic Rocks
Earth Science Chapter 3
Section 4

2. Introduction Metamorphism is the transformation of preexisting rock.
Rocks that undergo metamorphism tend to be different from the parent rock.
Parent rocks are the original rocks that the new rocks came from.

3. Types of Metamorphism
Metamorphism most often occurs in rocks that are buried deep below the earth’s surface.
There are 2 types of metamorphism:
Contact
Magma changes rock that it is in contact with
Small areas, Minor changes
Regional
Occurs when plates collide which increases temperature and pressure
Large areas, Major changes

4. Agents of Metamorphism
The major agents of metamorphism are heat and pressure.

5. Heat Most important agent of metamorphism
Provides the energy needed to drive the reactions
Comes from magma and deeper layers of earth
When the temperature increases the minerals in rock become unstable.
The minerals will change into new minerals that are stable at the higher temperatures.

6. Pressure Two types: confining and directed Confining
Associated with burial
all directions
increases with depth
Directed
Associated with plate movement
greater in one direction
associated with mountain building

7. Fluids
Fluids around minerals can make it easier for metamorphism to occur because the minerals can move easier.
If the temperature of the fluid increases, then reactions can occur faster.

8. Classification of Metamorphic Rocks
Foliated Metamorphic Rock
Layered or banded appearance.
The bands contain different minerals
Slate, schist, and gneiss (shale)
Nonfoliated Metamorphic Rock
No layers or bands
Only one mineral
Marble (limestone) and quartzite (sandstone)

9. Foliated Nonfoliated