1. Metamorphic Rock Notes

2. Metamorphism
Metamorphism is a process that changes the shape of something. Metamorphic rocks are those whose structure, texture, or composition has changed.

3. Formation
Metamorphic rocks form by heat, pressure, or a combination of the two.

4. Temperature
Most metamorphism occurs between 50˚C and 1000 ˚C. (50˚C=122˚F and 1000˚C=1832˚F).

5. Types of Metamorphism
Two types of metamorphism are contact and regional.

6. Contact Metamorphism Magma moves through the crust
Heats surrounding rock and changes it
Increased temperature causes minerals to change into other minerals
Magma in direct contact with surrounding rock = greatest change
Greater distance from magma = lower temperature = less change
Occurs near igneous intrusions

7. Regional Metamorphism
Pressure builds up in rock buried deep below other rock formations…
OR large pieces of Earth’s crust collide with each other
Increased temperature and pressure cause rock to become deformed and chemically changed
Occurs deep within Earth’s crust over thousands of kilometers

8. Composition
Metamorphic rocks are composed of minerals that change as temperature and pressure are applied.
Calcite
Garnet
Quartz
Hematite

9. Index Minerals
Index minerals are minerals that only form at certain temperatures and pressures.
Some common index minerals are biotite mica, chlorite, garnet, kyanite, muscovite mica, sillimanite, and staurolite.

10. Texture
The texture of metamorphic rocks is broken down into two groups: foliated and nonfoliated.

11. Foliated
Foliated: The texture of metamorphic rock in which the mineral grains are arranged in planes or bands

12. Nonfoliated
Nonfoliated: The texture of metamorphic rock in which the mineral grains are not arranged in planes or bands.
Commonly made of only one or a few minerals

13. Foliated or Nonfoliated?

14. Foliated or Nonfoliated?