Today’s Agenda… 4-25 Bellringer: What is the law of conservation of mass? Review Rock Cycle Worksheet (SP#1) Notes on Igneous Rocks (SP#2)

Understanding the Rock Cycle What is created when sedimentary rock is under heat and pressure? What is created when igneous rock is weathered or eroded? What is created when sedimentary rock is melted? What is created when metamorphic rock is melted and then cooled?

Understanding the Rock Cycle What is created when igneous rock is under heat and pressure? What is created when metamorphic rock is weathered and eroded? What is created when magma cools? What is created when sediment is compacted and cemented?

Igneous Rocks Study Pack #2

Today’s Goals… I can recognize magma and lava as the materials that cool to form igneous rocks. I can contrast the formation of instrusive and extrusive igneous rock. I can contrast granitic, basaltic, and andesitic igneous rock.

Inside the Earth Layers of the Earth Crust – outer most layer Mantle – molten rock (magma) Outer Core – melted metal Inner Core – solid metal ball that spins

Inside the Earth

Formation of Igneous Rocks When hot magma cools and hardens it forms igneous rock Igneous means “fire”

Formation of Igneous Rocks Magma comes from deep below Earth’s surface and is pushed upward because it is less dense than surrounding rock When magma reaches earth’s surface it is called lava

Types of Igneous Rocks Split into two groups Intrusive Igneous Rocks Extrusive Igneous Rocks How do they compare?

Intrusive Rocks Figure 6 on page 63 Rocks that form from magma below the surface Found only when the layers of rock and soil above them are worn away Takes a long time for them to cool Create visible mineral grains Coarse grained

Intrusive Rocks

Extrusive Rocks Formed as lava cools on the Earth’s surface Air and water cause it to cool more quickly Keeps mineral grains from growing large Fine grained

Extrusive Rocks

Compare them!

Types of Igneous Rocks Page 64 What is the difference between intrusive and extrusive igneous rock?

Volcanic Glass Some rocks cool so quickly they have few or no mineral grains present Some of the gases can also be trapped in the rocks and form holes

Classifying Igneous Rocks You can also classify these rocks by the magma from which they form Basaltic Andesitic Granitic What are the differences?

Basaltic Dense Dark colored Made up of iron and magnesium Black beach in Hawaii

Granitic Light-colored Lower density than basaltic Thick and stiff Lots of silica Can cause explosive eruptions

Andesitic Characteristics between basaltic and granitic