1. Notes
Metamorphic Rock

2. How can a rock change into another kind of rock?
Think About…
How can a rock change into another kind of rock?

3. Heat and Pressure
When you cook popcorn, you use heat to increase the pressure in the kernels until they explode.

4. Heat and Pressure
Popcorn is one example of how things can change because of heat and pressure.

5. Heat and Pressure
Metamorphism is the process in which a rock is transformed by heat or pressure-or both.

6. The original rock is called the parent rock.
Heat and Pressure
The original rock is called the parent rock.
The resulting rock is a metamorphic rock.

7. Heat and Pressure
Example: Shale is a parent rock that can become the metamorphic rocks slate, phyllite, schist, and gneiss.
Parent rock: Shale
Metamorphic rocks:
Slate
Phyllite
Schist
Gneiss

8. Heat and Pressure
Igneous, sedimentary, and even metamorphic rocks can all be parent rocks for metamorphic rocks.
Marble
Limestone

9. During metamorphism, rocks undergo many changes.
Heat and Pressure
During metamorphism, rocks undergo many changes.
Pressure causes a rock’s minerals to flatten out.

10. Melting and cooling ALWAYS produces igneous rock!
Heat and Pressure
Rocks do NOT melt during metamorphism, even though they experience high temperatures.
Melting and cooling ALWAYS produces igneous rock!

11. Heat and pressure break the bonds between the atoms.
Recrystallization is when the atoms re-bond differently after they are broken.

12. Recrystallization can result in:
Heat and Pressure
Recrystallization can result in:
Crystals growing larger
New minerals forming

13. Metamorphic Changes
The changes in a metamorphic rock depend on the type of parent rock and the amount of temperature and pressure.

14. The deeper in the crust, the greater the metamorphic changes.
Example: Shale near the surface becomes slate, while shale deep in Earth becomes gneiss.

15. Foliation
Foliation is an arrangement of minerals in flat or wavy parallel bands.

16. Foliation happens when rocks are under pressure.
Rock that is made of only one mineral will not show foliation.

17. At low levels of metamorphism, the bands of minerals are thin.
Foliation
At low levels of metamorphism, the bands of minerals are thin.

18. Slate can be split into thin sheets.
Foliation
Slate can be split into thin sheets.

19. With higher pressure and temperature, the rock will look shiny.
Foliation
With higher pressure and temperature, the rock will look shiny.

20. Foliation
At even higher temperature and pressure, the rock separates into light and dark bands.

21. Non-Foliated Rocks
Metamorphic rocks that do not have foliation are called non-foliated rocks.

22. A rock might be non- foliated because it is only made of one mineral.
Non-Foliated Rocks
A rock might be non- foliated because it is only made of one mineral.
Example: Marble is made of limestone, which is made of calcite.

23. Non-Foliated Rocks
A rock might be non- foliated because it has not experienced high pressure.
Example: Hornfels forms from rocks being heated by without melting.

24. Which kind of rock forms by recrystallization? Intrusive igneous
Review
Which kind of rock forms by recrystallization?
Intrusive igneous
Extrusive igneous
Sedimentary
Metamorphic

25. Review
2. An existing rock can change into another kind of rock when it is subjected to great
Pressure
Winds
Flooding
Foliation