2. ROCK ON! Introduction to the world directly beneath our feet

3. Why bother to study rocks?  Three reasons…  To find and utilize natural resources  Prepare for and maybe prevent natural disasters  Learn about earth’s natural history

4. Natural Resources  Coal  Petroleum  Gravel  Uranium  All metals used in construction  Aquifers  Earthquakes  Volcanoes  Landslides  Tsunami’s  Sink Holes  Foundation Problems Understand Disasters Earth’s History  All rocks tell an individual story about their past  If we look and listen closely, we can gain knowledge of our planet’s history

5. Three basic rock types  We classify rocks into three categories  These categories are distinguished by how each rock type is formed  Igneous Rocks  Metamorphic Rocks  Sedimentary Rocks

6. The Three Rock Types  Igneous – Rocks Born of Crystallized Fiery Molten Magma or Lava  Sedimentary – Rocks Born of Layered Water or Wind Deposits  Metamorphic – Rocks Born of a Change Deep Within the Earth

7. Magma or Lava….which is it?  Magma – hot molten rock that is beneath the surface of the earth  Lava – hot molten rock that has reached the surface of the earth

8. How does an Igneous Rock Form? CCCCrystallization – the solidifying of magma either at depth or on the exposed surface of the earth

9. The weather takes its toll  Weathering – rocks exposed at the surface undergo disintegration and decomposition from natural forces  Water, wind, glaciers, waves, heat, etc…  All these forces will break down rocks and transport the smaller broken down pieces  These broken down pieces are now called…

10. SEDIMENTS  Sediments – the eroded particles of rock that have been transported away from the original rock

11. Where’d my sediments go?  Lithification – literally means “conversion into a rock”  Lithification is when compacted and cemented sediments get buried and formed into a new rock  Hence, sedimentary rocks  Hence, sedimentary rocks More pressure is applied due to the addition of overlying layers Sediment grains are fused and cemented together as the water content is reduced

12. Check out all these sedimentary layers

13. Who dug up these buried rocks?  Two things can happen to sedimentary rocks:  They either get exposed at the surface as sedimentary rocks for us to find, or…  They continue to get buried deeper and deeper within the earth’s crust

14. How low can you go?  What happens when rocks get buried very, very deep?  The intense heat and pressure of deep burial will ultimately change the rocks into something new

15. Metamorphosis  Metamorphic Rock – a rock that has been changed from its original parent rock to a new form due to intense heat and pressure

16. And if you want to go even deeper?  Rocks that reach depths where the heat is extreme enough will turn back into molten rock material...  We have come full circle

17. Time, we need more time  All the processes of the rock cycle happen over incredible time spans  We cannot see the entire cycle in action, it takes much too long  We see the results of different stages of the cycle  Evidence for the cycle is found everywhere, in every rock

18. What Cycle are we Talking about?  ROCK CYCLE – The series of geologic processes that forms igneous, sedimentary, and metamorphic rocks and then breaks them down only to form new rocks again at a later time and place

19. THE ROCK CYCLE

20. ROCK CYCLE with Diagrams

21. To Review:  There are 3 main reasons to study rocks  There are 3 rock types: igneous, sedimentary, & metamorphic  Magma & Lava are not quite the same thing  Erosion must occur to form sediments  Deposition occurs to form sedimentary rocks  Heat & Pressure form metamorphic rocks  The Rock Cycle is not just a one way street  There are varying paths, and rocks can reform or skip whole sections of the cycle  Geologic processes take incredible amounts of time