1. 5.1 Lecture
Igneous Rocks

2. Igneous Rock Formation
MAGMA
LAVA

3. Type of Igneous rock formed depends on the composition of magma.
Magma- Mixture of molten rock, dissolved gases and mineral crystals.
Magma has the same elements in the Earths crust.
O, Si, Al, Fe, Mg, Ca, K, Na
The more Si in the rock the lighter the color

4. Magma has 3 Classifications
Based on the amount of Silica it contains.
Basaltic – (45 – 52)%
Andesitic – (52-66)%
Rhyolitic – (more than 66)%

5. Once magma is free of pressure…
Gas will escape into the atmosphere
This release of gas changes the composition of lava from the magma which it came.

6. Magma can be formed by melting
The Earths Crust
The Earths Mantle

7. Rocks and Minerals Contain Water
As the water content increases, the melting point decreases…
allowing the rock or mineral to melt faster.

8. Partial Melting

9. Bowens Reaction Series

10. The first minerals that crystallize are the last to melt.