1. Igneous Rocks

2. Igneous
Metamorphic
Sedimentary
3 types of rocks

4. Igneous rocks are formed from molten rocks that has cooled and hardened.
Ship Rock, New Mexico
Formed when magma in a volcano cooled slowly
Igneous Rocks

5. Magma (or Lava) cool and crystallize to form igneous rock.
Igneous Rocks

6. There are two types of Igneous Rock. Intrusive and Extrusive
Igneous Rocks

7. Extrusive Igneous Rock is formed from lava, which is on the surface.
Intrusive Igneous Rock is formed from magma, which is below the surface.

8. What is the difference between magma and lava
What is the difference between magma and lava? Lava is on the earth surface and magma is below.
Molten rock that flows on the surface of the Earth is lava.
Molten rock that is below the surface of the Earth is Magma.

9. Textures of Igneous Rocks
Intrusive— large crystals
WHY? The inside of the Earth is VERY hot! Therefore, the magma cools slowly creating larger crystals
Extrusive— small crystals
WHY? Earth’s surface is much cooler, and lower temperatures mean rocks cool quickly, not leaving enough time for large crystals to form.
Textures of Igneous Rocks

10. Igneous rocks are dominated by silicate minerals.
Silicates

11. Molten rock with lower amounts of silica flows faster than molten rock with higher amounts of silica.
If lava has more silica, it will move slower than lava with less silica.

12. Extrusive Igneous Formations
Lava spread = small amounts of silica
Explosive eruptions = large amounts of silica
Extrusive Igneous Formations

13. Where are many Igneous Rocks found? Divergent boundaries and volcanoes.

14. Igneous rock undergoes weathering (or breakdown) to form sediment.
So it becomes……………………
Sedimentary Rock
The Rock Cycle

15. Of the following three types of rocks, igneous rocks are the hardest.

16. Stone Mountain

17. The Stone Mountain granite is a relatively small granite pluton that covers an area less than a county in size.
Stone Mountain

18. Stone Mountain is made of granite and is an igneous rock.

19. Magma that cools and hardens forms an intrusive igneous rock
Lava that cools and hardens forms an extrusive igneous rock