1. A ROCK IS
A naturally occurring, solid, mixture of one or more minerals or organic matter
Rocks are
Classified into 3 groups based on how they are formed: igneous, sedimentary, and metamorphic

2. Texture and composition give clues as to how rocks are formed, and are used to classify rocks
Rocks are always changing form in a cycle called the Rock Cycle

3. Coarse Medium Fine Rock Classification Composition Texture
the type of minerals a rock contains
Composition
the size, shape and arrangement of the minerals that make up a rock. Can be fine, medium, or coarse.
Texture
Medium
Fine

4. The Rock Cycle
The main idea of the rock cycle is that rocks are continually changing from one type to another and back again
The elements that make up a rock are never created or destroyed - instead, they are constantly being recycled.

7. Types of Forces That Create Rocks
Constructive
Builds something up or creates something new
Destructive
Breaks something down or destroys something
Explain how something can be BOTH…

8. In your notes… Definition Origin/Formation Classes/Groups
Definition
Origin/Formation
Classes/Groups
Method for Grouping
Other Info/
Example
Igneous
Sedimentary
Metamorphic

9. Igneous Rock Form when magma cools and hardens.
Sometimes look shiny and glasslike if lava cools quickly
Sometimes have tiny holes and spaces if gas is trapped in the rock as it cools
Two examples are: Basalt and Obsidian

10. Igneous Rocks Classes Extrusive rocks- formed by cooling lava
Texture:
glassy (obsidian)
porous (pumice)
fine-grained (basalt)
Intrusive rocks- formed by cooling magma
coarse-grained (granite)

11. Formation of Intrusive Igneous Rock

12. Obsidian…
Basalt…

13. Granite…
Coarse Grained Texture
Pumice…
Porous Texture

14. Sedimentary Rock Formed from particles called sediments
Fairly soft and break easily
Contain sand, pebbles, stones, and is the only rock to contain fossils
Form at or near Earth’s surface
Most have layers or strata

15. Sedimentary Process 1. Weathering (breaking down of rock)
2. Erosion (movement of sediments)
3. Deposition (collection of sediments)
4. Compaction & Cementation

16. Weathering- determined by rock type and climate
Chemical Weathering:
Mechanical Weathering
Root Action
Frost Action
Moss

17. (By the way…)

18. Five Agents of Erosion
Gravity
Wind
Running water
Glaciers
Waves

19. Examples of Deposition
Nile River Delta
Lateral moraine
Cape Cod

20. Compaction & Cementation

21. 3 Sedimentary Rock Types
Clastic: sediment fragments cemented together by minerals
Ex: Conglomerate
Organic: form from the remains of animals or plants
Ex: Coal
Chemical: solutions of dissolved minerals & water (evaporation)
Ex: Rock Salt

22. Metamorphic Rock
Formed under the surface of the Earth due to extreme heat and pressure
Have ribbon-like layers and may have shiny crystals formed by minerals cooling slowly over time
Two examples are: Gneiss and Marble

23. Think about CAKE BATTER in an oven…
Metamorphic Rocks
Think about CAKE BATTER in an oven…
Formed by tremendous heat & pressure, and chemical reactions inside the crust.
Formed from all three rock types.

26. Types of Metamorphic Rock
Slate
Foliated (bands or layers)
Ex: schist, slate, gneiss
Gneiss
Schist

27. Types of Metamorphic Rock
Unfoliated (no bands or layers)
Ex: marble and quartzite
Quartzite

28. Warm-up: How are igneous rocks formed?
What’s the difference between extrusive and intrusive igneous?
What would their textures most likely look like?

29. Now: Complete the Rock Cycle Interactive with your partner
Study for the Quiz tomorrow
Work on the Green review for Thursday (test next Tuesday)
Work on choice items for conference before Friday

30. Summary

31. Warm-up:
List as many steps of the rock cycle as you can without using notes.
What is the main idea of the rock cycle?
Explain how rock is continually recycled in the rock cycle.

32. Warm-up: Describe how ALL sedimentary rocks in general are formed.
What are the 3 subtypes of sedimentary rocks?
What is the difference between weathering and erosion?