1. 3 Major Rock Groups

2. 3 Major (Geologic) Rock Groups
Igneous Rock Sedimentary Rock Metamorphic Rock

3. Identifying Rocks Igneous pattern Metamorphic pattern
Sedimentary pattern

4. Basalt lava (glowing rock) oozes over basalt lava flow
A. Igneous Rock
-Forms when hot, liquid, rock crystallizes (cools and solidifies).
Magma forms 3 ways:
Rock is heated
Pressure released
Change composition
Holt Online Visual: Comparing Int. & Ext Igneous Rocks
Basalt lava (glowing rock) oozes over basalt lava flow

5. Intrusive Igneous Rock
-Forms inside Earth
-slow cooling

7. b. Extrusive Igneous Rock -Forms on surface (exterior) of Earth -Fast cooling

8. a. Composition of Igneous Rock
Felsic Rock
-Light colored
-made of aluminum, potassium, silicon, and sodium.
Mafic Rock
-Dark colored
-Made of calcium, iron, and magnesium.
Fine-grained
Course-grained
Course-grained
Fine-grained

9. b. Texture of Igneous Rock
-Slow cooling forms large crystals. (Coarse-grained Texture)
-Fast cooling forms small crystals. (Fine- grained Texture)

10. Fast cooling = small crystals
-Rate of cooling influences crystal size.
Fast cooling = small crystals
Slow cooling = large crystals
Show Holt Visual: Igneous Rock Texture

12. Pop Quiz! What size crystal forms from extrusive rock?
What is one way magma forms?
Generally speaking what color are felsic rocks?
4. Quality of rock based on the size,
shape, and arrangement of grains is
referred to as…
5. What are the 2 characteristics that geologist
study to identify rock:?

13. Igneous Rocks Rock ID practice
Use the rock key to identify the various rocks on your table:
Igneous Rocks
Classified according to composition & texture
Glassy- shiny and look like glass, not organized into crystals.
Ex: obsidian

14. Fine-grained-made of interlocking crystals.
Ex: basalt
BASALT

15. More Igneous Rocks…
Course Grained Texture- Granite

16. More Igneous Rocks…
Porous- no crystals, cools rapidly, looks like a sponge.
Ex: pumice

17. More Igneous Rocks…
Diffferent size crystals locked together

18. More Igneous Rocks…

19. Sedimentary Rock Strata layers of rock.
Stratification The process in which sedimentary rocks are arranged in layers.
Holt Visual Sedimentary Rock Cycle

20. 3 Types of Sedimentary Rock
1. Clastic forms when rock or mineral fragments are cemented together.

21. 2. Chemical forms when minerals crystallize out of solution, such as sea water, to become rock.

22. 3. Organic forms from the remains of once- living plants and animals.
Ex: Limestone
Coal
Chalk

23. Metamorphic Rock
-Rocks that have undergone a change in texture, structure, or composition.
-Changes in heat and pressure cause rocks to change from one form to another.

25. Origins of Metamorphic Rock

26. Contact Metamorphism
Rock undergoes metamorphism when it comes in contact with magma or is heated by nearby magma.

27. Regional Metamorphism
-Pressure builds up in rock that is buried deep below rock formations or when large pieces of rock collide.

28. Textures of Metamorphic Rock
Foliated the texture of metamorphic
rock in which the mineral
grains are arranged in planes
or bands.

29. Nonfoliated
-The texture of metamorphic rock in which the mineral grains are not arranged in planes or bands.