1. ROCKS Rock!

2. Earth’s Layers

3. Compare & Contrast Rocks!
Look at the rock samples and write a short paragraph ( at least 5 COMPLETE sentences) describing how the rocks are similar and how they are different.

4. What is a ROCK?
Solid mass of mineral or mineral-like matter that is naturally occurring
Most rocks are made up of more than one mineral
Some rocks are made up of no minerals
Coal=organic material

5. Three Major Types of Rocks
Igneous
Intrusive
Extrusive
Sedimentary
Metamorphic

6. The Rock Cycle
Interactions among Earth’s water, air, & land can cause rocks to change from one type to another

7. Magma or Lava? Magma is molten material deep beneath Earth’s surface
When magma reaches the surface it becomes lava

8. Important Vocabulary to Understand the Rock Cycle
Weathering—process by which rocks are physically and chemically broken down by water, air, & living things to produce sediment
Sediment—weathered pieces of earth material

9. What drives the rock cycle?
Igneous and metamorphic rocks are formed by processes from Earth’s interior heat
Sedimentary rocks are produced by processes on and near Earth’s surface
Weathering and the movement of weathered materials are external processes powered by energy from the sun & gravity

10. Think! Turn to the person sitting next to you and discuss:
What do you notice about the rock cycle?

11. IGNEOUS ROCKS!!!

12. Igneous Rocks
Intrusive igneous rocks—form when magma hardens beneath Earth’s surface
Extrusive igneous rocks—forms when lava hardens

13. Quick Check
How are magma and lava the same?
How are they different?

14. Classification of Igneous Rocks
Coarse Grained Texture
Slow cooling=large crystals
Fine Grained Texture
Fast cooling=small, interconnected minerals grains
Which is coarse grained & which is fine grained?

15. Classification of Igneous Rocks
Glass Texture—no time for ions in the lava to arrange into crystals before hardening
Randomly distributed ions
Porphyritic Texture—rocks with very different-size minerals experience different rates of cooling

16. Classification of Igneous Rocks
Granitic Composition—light-colored silicate minerals quartz & feldspar are the main minerals
Most granitic rocks contain about 10% dark silicate minerals (such as biotite mica & amphibole)

17. Classification of Igneous Rocks
Basaltic Composition—contain many dark silicate minerals & plagioclase feldspar
Rich in magnesium & iron
Typically darker & denser than granitic rocks because of the iron
Make up Earth’s ocean floor

18. Classification of Igneous Rocks
Andesitic Composition—between granitic & basaltic
At least 25% dark silicate minerals, mainly amphibole, pyroxene, & biotite mica
Peridotite—almost entirely dark silicate minerals (olivine & pyroxene)
Ultramafic—rare at Earth’s surface but much of the upper mantle

19. Classification of Major Igneous Rocks

20. Rock Joke Break!

21. Sedimentary Rocks!!!

22. Formation of Sedimentary Rock
Clastic Sedimentary Rocks—made of weathered bits of rocks and minerals
Chemical Sedimentary Rocks—dissolved minerals precipitate from water solutions

23. Clastic Sedimentary Rocks
Made of mostly clay minerals & quartz
Grouped by size of the sediments
Conglomerate=rounded, gravel-size or larger particles
Breccia=angular particles
Sandstone=sand-sized grains

24. Chemical & Biochemical Sedimentary Rocks
Dissolved substances precipitate, or separate, from water solutions
Water evaporates or boils off leaving a solid product
Ex: limestone, rock salt, chert, flint, and rock gypsum
Biochemical Sedimentary Rocks=shells & skeletal remains of organisms that settle to the ocean floor

25. Features of Sedimentary Rock
Each layer of sedimentary rock records a period of sediment deposits
Fossils are unique to some sedimentary rock

26. Classification of Sedimentary Rocks

27. Metamorphic Rocks!!!

28. Formation of Metamorphic Rocks
Existing rocks are changed by heat & pressure
What does metamorphism mean?
Come up with the best definition possible with the person next to you!
Changes form

29. Formation (Continued)
Contact morphism=magma intrudes (forces its way into) rock
Marble often forms when magma intrudes into limestone

30. Formation (Continued)
Regional metamorphism
Large areas of rocks are subjected to extreme pressures & temperatures during mountain building
Intense changes occur at a large scale level

31. Agents of Metamorphism
Heat
Provides energy needed to drive chemical reactions
Cause existing minerals to recrystallize
Magma & change in temperature from depth
Pressure (stress)
Increases with depth
Causes the spaces between mineral grains to close
Results in more compact rock with a greater density
Reactions in solution
Hot solutions promote recrystallization
Can deposit new minerals in the rocks

32. Classification of Metamorphic Rocks
Foliated metamorphic rocks
Layered or banded appearance
Nonfoliated metamorphic rocks
No banded texture
Most contain only one mineral
Marble is an example—made up of calcite

33. Classification of Metamorphic Rock

34. Think!
Use what you have learned about the rock cycle to explain the following statement:
One rock is the raw material for another rock
Your friend shows you a rock with distinct layers. How can you and your friend determine if the rock is a sedimentary rock of a metamorphic rock?