1. Types of Rocks
Ms. Sikes

2. Igneous Rocks Form from magma 2 types:
Intrusive: (inside) rock formed from magma beneath the earth’s surface
Extrusive: (outside) rock formed as a result of volcanic activity at or near earth’s surface

3. Igneous Rocks cont… Texture is determined by how fast it cools.
Slow = coarse (bumpy) texture
Fast = fine (smooth) texture

4. Examples of Igneous Rocks
PUMICE
OBSIDIAN
GRANITE: the most abundant igneous rock

5. Sedimentary Rocks
Formed when sediment (gravel, sand, mud, silt) forms layers and are compacted (smushed) together
Forms at the earth’s surface (often in the bottom of lakes and oceans)

6. Sedimentary Rocks cont…
3 types of Sedimentary Rocks:
1. Clastic- made of rock fragments and cemented together by a mineral like calcite or quartz (these look grainy) (sandstone)
2. Chemical- form from dissolved minerals in water (halite)
3. Organic- form from fossils of animals (coal)

7. Characteristics of Sedimentary Rocks
Usually in layers (strata)

8. Examples of Sedimentary Rocks
See page 373 in book

9. Metamorphic
What does the word metamorphosis mean? Where have you heard it before?

10. Metamorphic Rocks Were originally sedimentary or igneous rocks
Formed when: heat or pressure is different from what the rock is used to and it changes the rock
Usually rocks change at temps between 50 degrees Celsius to 1000 degrees Celsius

11. Ways that rocks can metamorphasize
1. rock is heated by nearby magma
2. pressure builds up in rocks which causes it to change

12. Texture of Metamorphic Rocks
Foliated: mineral grains are arranged in bands
Nonfoliated: mineral grains are randomly arranged
Marble
Slate

13. Picture tour of book
Look on pages

14. Classify your rocks Which ones are sedimentary?
Which ones are Igneous?
Which ones are metamorphic?
Can you name any of them?

15. Exit Ticket On a post it note:
Explain how each type of rock is formed:
1. metamorphic
2. sedimentary
3. igneous