1. Metamorphic rocks

2. Metamorphic Rocks
Metamorphic rocks are formed deep within the Earth’s Crust
“Meta” in Latin means change, “Morph” in Latin means shape
Thus, metamorphic means a physical change of one rock into another by intense heat and pressure

3. The rock cycle

4. Contact metamorphism
When surrounding rock comes in contact with magma but does not melt they change into a harder type of metamorphic rock

6. The lava flow exposed in this road cut near Alturas, California, has baked the mud beneath it into brick-red shale, a case of contact metamorphism.

7. Limestone to marble

8. Quartz sandstone to quartzite

9. Regional metamorphism
When enormous pressure builds up in rock that is deeply buried under rock formations
When large pieces of the Earth’s crust collide with each other
Occurs over a large area during mountain formation and subduction

10. Regional Metamorphism

12. Pressure and temperature relation
As the temperature increases, less pressure is needed
As the pressure increases, less temperature is needed

13. Composition of metamorphic rock
When the temperature and pressure of a rock changes, the minerals that were present in the rock when it formed may no longer be there
Under intense heat and pressure, calcite, quartz, and hematite combine and recrystallize into the metamorphic mineral garnet

14. Texture of metamorphic rock
Foliated Metamorphic Rocks
Mineral grains are aligned by pressure
Looks like the pages in a book

15. More foliated rocks

16. Texture of metamorphic rock
Nonfoliated Metamorphic Rocks
Do not appear to have any regular pattern