Bellwork November 3 rd Make a venn diagram explaining the similarities and differences between metamorphic and igneous rocks.

Igneous Rocks

How Does Igneous Rock Form? Form when hot, liquid rock (magma) cools and hardens

How Does Magma Form? 1.Increase in temperature: when temperature increases, minerals in rock melt 2.Decrease in pressure: if hot rock rises to the surface, the pressure goes down, and the rock will melt 3.Addition of fluids: when fluids mix with rock, the rock’s melting temperature decreases and the rock can melt

Check for Understanding Give three ways that magma can form.

How Do Igneous Rocks Form, cont. When magma cools, mineral crystals form Similar to ice Magma = different compounds Compounds = different minerals Each mineral becomes solid at different temperatures As magma cools, different parts become solid at different temperatures

How Do Igneous Rocks Form? Magma Mineral Magma Igneous Cools Crystals Cools Rock Start To More Form Form

Check For Understanding Why do different parts of magma become solid at different times?

How Are Igneous Rocks Classified? Composition Texture

Composition – Felsic Rich in Sodium, Potassium, and Aluminum Combine to make light-colored minerals Felsic igneous rocks are light-colored Examples are granite and Rhyolite – Mafic Rich in Iron, Magnesium, and Calcium Combine to make dark-colored minerals Mafic igneous rocks are dark-colored Examples are gabbro and basalt

Check for Understandin Give two differences between felsic and mafic igneous rocks.

Texture Texture of any rock is determined by the sizes of the grains in the rock Texture of an igneous rock depends on how fast the magma cooled Cools fast – small crystals form (fine-grained texture) Cools slow – large crystals form (coarse- grained texture)

Check for Understanding Give an example of a felsic, fine-grained igneous rock. Give an example of a mafic, coarse-grained igneous rock.

Texture: Intrusive Igneous Rocks Intrusive Igneous Rocks – Forms when magma cools below the Earth’s surface – Magma cools slowly, so most will have coarse- grained texture

Check for Understanding Write your own definition for intrusive igneous rock.

Texture: Intrusive Igneous Rocks Stock – large body of intrusive rock Batholith – largest kind of intrusive rock body Dike – sheetlike body of intrusive rock that cuts across other rock layers Sill – sheetlike body of intrusive rock that is parallel to other rock layers Volcanic Neck – forms when a dike or stock is exposed to the surface. The rock around it erodes away and only the igneous rock is left behind

Check for Understanding Give four kinds of intrusive rock bodies.

Extrusive Igneous Rocks – Forms when lava cools – Common around volcanoes – Lava cools quickly, so most will have fine-grained texture

Check for Understanding Why do extrusive rocks have very small crystals or no crystals?