1. The Rock Cycle “Where do rocks come from?”

2. Rocks and Minerals  Rocks are made of minerals.  Examples of minerals are:  Wakabayashilte, azurite, and galena.

3. Minerals change when:  They are heated  They are put under pressure

4. Heat and pressure comes from:  Earth’s inner workings (convection current)  Outer Earth forces (gravity, climate)

5. Without constantly changing heat and pressure  rocks would all be the same  geology would be very boring (no earthquakes, volcanoes or tsunami)

6. Because Earth is constantly changing:  Three major rock types: Igneous Metamorphic Sedimentary

7. One type of rock changes to another through:  Heat  Pressure  Erosion and deposition

8. This is called:  THE ROCK CYCLE

9. Reminder:  Magma is molten (melted) rock

10. Igneous Rocks  Form when magma solidifies

11. Types of Igneous Rock  Extrusive: when magma comes to the surface in a volcanic eruption

12. Types of Igneous Rock  Intrusive: when magma cools and solidifies slowly within the Earth  (note: intrusive rocks are found on the surface due to erosion, or uplifting)

13. Igneous rocks change:  Through weathering (aka: erosion) Wind Water Ice

14. The sediment is…  deposited on the sea floor  water pressure compacts and cements it

15. And becomes…  Sedimentary Rocks

16. Over time:  More layers of sediment are deposited  Pressure grows greater  Heat grows greater  The sedimentary rock recrystalizes (the minerals change again)

17. And becomes…  Metamorphic Rock

18. The temperature…  rises again  pressure increases  And the Metamorphic rock…

19. Becomes magma.  And the cycle begins again.

20. The End For Now…

21. Glossary Terms  Igneous (adj.) Formed by the solidification of molten rock; produced by volcanic heat.

22. Glossary (continued)  Metamorphic (adj.) A rock that has become more compact and more highly crystalline due to pressure and heat. A rock that has been changed. These are both examples of Gneiss – a type of metamorphic rock

23. Glossary (continued)  Sedimentary (adj.) Material deposited by water, wind, or glacier.