1. Igneous Rock
How do these form??

2. Answer Hot, liquid rock, or magma cools + solidifies
The type of I. rock depends on the composition of magma and the amount of time it takes to cool

3. Origins of I. Rock 3 ways I. rock forms Rock is heated
Pressure is released
Rock changes composition

4. Magma cools is solidifies = I. rock
This happens the same way H2O freezes
Magma can be made up off different minerals and each of their own melting point
Results some minerals are melting why others are still in the hard stage

5. Composition + Texture of I. Rock
pg. 99
Light colored = less dense so cooled fast
Minerals = Aluminum, Potassium, Silicon, Sodium
Called felsic rock
Dark colored = more dense- cooled slower
Minerals = Calcium, iron, magnesium, a little silicon
Called mafic rock

6. The longer the magma has to cool the bigger the crystals will be = coarser texture of I. rock
Less time –smaller crystals = finer texture of I. rock

7. Igneous Rock Formation
Happens above and below Earth’s surface
Above= volcanoes

8. Intrusive Igneous Rock
This is magma that intrudes/pushes, into surrounding rock below Earth’s surface and cools
Has coarse-grained texture (large crystals)

9. Plutons-large, irregular shaped intrusive bodies
Batholiths- large igneous intrusive-under round
Stocks-intrusive areas that are over smaller underground areas
Dikes- cut across other rocks –can be above ground
Sills-sheet-like intrusions that run parallel-underground

11. Extrusive Igneous Rock
Forms when magma erupts or extrudes onto Earth’s surface
Usually around volcanoes
Lava flow forms when magma is released

12. Cools quickly-very small to no crystals-fine texture
Fissures are long cracks that magma can come out off
Can be found on ocean floor-where plates come together
Can create a lava plateau