Three Types of Rocks

Unit 3 Lesson 3 - Three Classes of Rock

How do rocks form? ​

By the end of this lesson, you should be able to describe the formation and classification of sedimentary, igneous and metamorphic rocks.

Multiple Choice

All rocks form beneath Earth's surface?

• True

• False

Multiple Choice

Some rocks are made up of materials from living things.

• True

• False

Multiple Choice

Some rocks take millions of years to form.

• True

• False

Multiple Choice

All rocks are made up of the same kinds of materials.

• True

• False

Multiple Choice

Some rocks form from particles of other rocks.

• True

• False

Open Ended

How do you think rocks might form as a result of the volcanic activity shown here?

• A combonation of one or more minerals or organic matter = Rock

• Scientists look at composition and texture.

• The minerals or organic matter that a rock contains determine its composition.

• The size, shape, and positions of the grains that make up a rock determine its texture.

How are rocks classified?

​A Rocky World

Multiple Select

What two properties used to classify rocks?

• Compositon

• Density

• Texture

• Color

Coarse Grained - Large and Easy to see

Fine Grained - Microscope

Gives clues on how and where it formed.

Igneous - Time taken to cool

Metamorphic - Comp/Temp/Press

​By Texture

Most rocks are made up of the minerals quartz and feldspar.

They contain large amounts of the compound silica.

Other rocks have different compositions.

​By Mineral Composition

How are Rocks Classified?

Multiple Choice

What would you classify the texture of this rock as?

• Fine Grained

• Medium Graine

• Coarse Grained

Multiple Choice

What would you classify the texture of this rock as?

• Fine Grained

• Medium Graine

• Coarse Grained

Multiple Choice

What would you classify the texture of this rock as?

• Fine Grained

• Medium Graine

• Coarse Grained

• Form when hot liquid magma cools into solid rocks

• Magma can cool under Earth's surface forming Intrusive Igneous rocks.

• Magma can come to the surface as lava and form Extrusive igneous rocks.

​

What are two kinds of igneous rocks?

​Igneous Rocks

What are two kinds of Igneous Rocks?

Some text here about the topic of discussion

• Lava erupts onto Earth's surface and cools.

• Common around volcanoes and fissures

• Very small crystals - fast cooling

• Ex. Basalt and obsidian

​Extrusive Igneous Rock

• Magma cools in cracks and chambers below the surface

• Cools Slowly = Large visible crystals

• Generally coarse grained texture

• Ex. - Granite and Diorite

Intrusive Igneous Rock

Open Ended

How can you tell that this diorite is an intrusive igneous rock?

Open Ended

What is the relationship between the rate at which magma cools and the texture of the resulting igneous rock?

Multiple Select

Select the characteristics of an Intrusive Igneous Rock...

• Forms Near Earth's Surface

• Forms within Earth's crust

• Crystal growth is slow

• Crystal growth is rapid

• Coarse-grained texture

Multiple Select

Select the characteristics of an Intrusive Extrusive Rock...

• Forms Near Earth's Surface

• Fine Grained Texture

• Crystal growth is slow

• Crystal growth is rapid

• Coarse-grained texture

• WEDCC - You know it!

• Clastic Sedimentary

  • Cemented by calcite or quartz

  • Size of sediment classifies

  • Fine Grained (too small to see)

    • mudstone, siltstone, shale

  • Medium Grained

    • Sandstone

  • Coarse Grained

    • Breccia and Conglomerate

​

What are the three types of sedimentary rock?

Sedimentary Rock

• Chemical Sedimentary

  • formed when water/seawater evaporates

  • Concentrated minerals precipitate out of the solution as crystals.

  • Halite (Salt or NaCl) will form when shallow bodies of salt water evaporate.

​

What are the three types of sedimentary rock?

Sedimentary Rock

Multiple Choice

How would you describe the texture of the halite in the image?

• crystaline

• fine grained

• medium grained

• Organic Sedimentary

  • Made from the remains of once living plants and animals (fossils).

  • Marine organisms = fossilferous limestone

  • Coquina - Shells cemented together by calcite

  • Chalk

  • Coal - Plant material exposed to tremendous heat and pressure.

​

What are the three types of sedimentary rock?

Sedimentary Rock

Multiple Select

Which of the following are organic sedimentary rock?

• lime stone

• coquina

• coal

• chalk

Metamorphic Rocks

Foliated

• Grains arranged in planes or bands = foliation.

• With increasing temperature and pressure the same rock can go through a number of transformations based on the temperature pressure and different materials.

What are two types of metamorphic rock?

Non-Foliated

• Do not have mineral grains arranged in planes or bands.

• Made of only a few minerals

• Mineral grains may change size or shape, some change into another mineral

• Quartzite and Marble

Open Ended

What are two characteristics of non-foliated metamorphic rocks?