1. Metamorphic Rocks

2. “Metamorphic”
“Metamorphic” means Change!
Biochemical Limestone
Marble

3. Metamorphic Rock Sources
Metamorphic rocks are formed when:
1.Igneous
2. Sedimentary or
3. Pre-existing Metamorphic rocks are
changed

4. Metamorphic Rock Classification
Metamorphic Rocks are classified based on:
1. Formation Conditions (where formed)
2. Texture
3. Parent Rock (what rock, or rock type, it came from)
Quartzite- Fine Grained
Gneiss- Foliated

5. Common Metamorphic Rocks
Rock Name
Parent Rock
Slate
Shale or Mud
Mica
Gneiss
Granite
Quartzite
Sandstone
Marble
Limestone

6. Temp C
Temp F
Coal
Limestone
Sandstone
Basalt
Shale
Index Minerals
Lignite Bituminous
500
Anthracite
300
600
Graphite
Marble
Slate
Chlorite
700
Greenstone
800
Quartzite
Phyllite
Biotite
900
Schist
Garnet
1000
Amphibolite
Staurolite
1100
Gneiss
Kyanite
1200
Sillimanite
Melting Begins

7. Slate

8. Mica

9. Gneiss

10. Quartzite

11. Marble

12. Schist

13. What Causes Metamorphic Rocks to Form?
Metamorphic Rocks are formed when preexisting rocks are changed by:
Heat
Pressure
And

14. Sources of Heat
Increase in Temperature due to Deep Burial (20-30 degrees Celsius per kilometer below the surface). Due to radioactive decay.----Regional- Metamorphism
Increase in Temperature due to Plate Friction ( degree Celsius per km below the surface) Dynamic Metamorphism
Intrusion by hot Magma. ----Contact Metamorphism

15. Sources of Pressure
Weight of Overlying Rocks (1 cubic foot of granite weighs 167 pounds)
Created by converging plates (Converging- Boundaries) or those
Transform Boundaries (side-by-side movement)

16. Effects of Metamorphism on Rocks
Impurities such as holes and fossils destroyed.

17. Effects of Metamorphism on Rocks
Pore Space between grains is lost due to Compression.
Rock density increases.

18. Effects of Metamorphism on Rocks
Mineral Grains are flattened, enlarged and elongated.

19. Types of Metamorphism

20. Regional Metamorphism

21. Regional Metamorphism
Occurs in large areas.
Occurs in response to deep burial by large areas of rock.
Occurs with Mountain Building (Collision Boundary).

22. Regional Metamorphism

23. Regional Metamorphism

24. Increasing metamorphic grade
Foliated Metamorphic Rocks
Increasing metamorphic grade
Increasing foliation
phyllite
schist
gneiss
migmatite
slate
(partially melted)
(low grade)
(high grade)

25. Dynamic Metamorphism
Occurs between moving plates (very localized and happens quickly).

26. Thermal or Contact Metamorphism
Occurs when rock comes into contact with Magma or hot Pore Fluids (Geysers and Hot Springs).

27. Thermal or Contact Metamorphism