1. Earth Science Chapter 8: Rocks

2. Lesson 2: Igneous Rocks Learning Targets By the end of the lesson, I will be able to: 1.Explain how igneous rocks form 2.Compare intrusive and extrusive igneous rocks 3.Identify samples of igneous rocks Pg 181 Textbook

3. How igneous rocks form Deep below earth’s surface temperatures reach around 1,400 degrees C Minerals melt to form magma (hot liquid rock formed inside the earth) Magma sometimes rises through gaps in the surface of the earth The rock cools thus forming igneous rock

4. Intrusive Rocks Igneous rock that forms underground is called intrusive rock Rock forms slowly (large crystals due to this) The size of the minerals crystals in an igneous rock are called the rock’s texture Intrusive rocks have a course-grained texture Most common is granite Can be any color (mixture of minerals)

5. Extrusive rocks When magma reaches the earth’s surface it is called lava Lava cools and forms extrusive rock Cools quickly so does not have many crystals (fine-grain texture) Most common is basalt Volcanic eruptions Glassy texture

6. Recap Learning Targets By the end of the lesson, I will be able to: 1.Explain how igneous rocks form 2.Compare intrusive and extrusive igneous rocks 3.Identify samples of igneous rocks Assignment