The Rock CycleThe Rock Cycle

How can this be a cycle?

• What rock forms when magma cools?– igneous rock

• How is sedimentary rock formed?– pressure and cementing of sediment

• What happens to rock when it melts?– It’s magma

What are igneous rocks?Rocks formed from magma

that’s cooled.

How are granite and basalt related?

Continental crust = mostly granite (large crystals formed underground).

Oceanic crust =

mostly basalt (small crystals formed at the surface).

They are both igneous rocks !

Where do sedimentary rocks come from?They’re formed by layers

(sediments) that are the pieces of other rocks,

that are (stuck or glued) cemented

by minerals that were

left behind by water (deposited).

How are sand, sandstone, and conglomerate connected?

Sand comes from weathering & erosion. Wind, water, or ice

cause pieces of rock to break off of larger rocks…

…sandstone and conglomerates; they’re all sedimentary rocks that were cemented together with the pieces of other rocks.

What are metamorphic rocks?

Rocks formed when existing rocks are changed by heat and pressure.

Heat and Pressure

Sedimentary

(limestone)

Metamorphic

(marble)

How are shale and slate connected?

The sedimentary rock, shale is changed into the metamorphic rock, slate by heat and pressure.

shale slate

What are the 3 classes of rock?Petrologists classify rocks by how they form.

2. ___________ - pieces of minerals, rock,

and living things that compacted together

1. ________ - melted rocks (minerals) that have cooled

3. __________ - any rock that is changed by heat and pressure (not fully melted)

Igneous

Sedimentary

Metamorphic

The Rock Cycle

1. Rocks are minerals cemented together2. There are three classes of rock:

Igneous: formed from cooling magmaMetamorphic: igneous, sedimentary, or

metamorphic rock changed by heat/pressure

Sedimentary: formed from sand (broken down rock) cemented together.

3. As you go deeper in the Earth, thetemperature increases or gets hotter.

Concept and Challenges – What are rocks?

4. Igneous rocks are made from magma. As magma cools it forms igneous rocks.

5. The three main minerals that make up granite are

quartz, feldspar, and mica

6. Obsidian does not have crystals because it is lava that cooled too quickly

7. Sediments are small parts of rock that are carried and deposited by water, wind, or ice

8. Acid reacts with calcium, and because the sedimentary rocks from the White Cliffs of Dover have calcium carbonate (CaCO3), the acid would react.

9. Clastic rocks are made up of smaller rocks that are nonliving, but nonclastic rocks are made up of dissolved minerals or dead plants and animals.

10. Metamorphic rocks are formed by rocks that are changed by heat and pressure.

11. You can make bread from water, flour, salt, and yeast. First, you mix the ingredients. Then, you bake the mixture in an oven.

12. The minerals in the rocks melt and recrystallize into minerals that form bands.

Melting

MAGMA

SEDIMENTARY ROCK METAMORPHIC

ROCK

IGNEOUS ROCK

SEDIMENT

Melting and CoolingMelting

Weathering,Cementing Weathering

Weatheringggg

Heat andPressure

Heat andPressure

The Rock CycleDo you know…1. What is the connection between shale

and slate?2. What is the connection between granite

and basalt?3. What is the connection between obsidian

and pumice?4. What is the connection between sand,

sandstone and conglomerate?

Shale and SlateThe sedimentary rock shale is changed into the metamorphic rock slate by heat and pressure.

Granite and BasaltThey are both igneous rocks. Granite makes up most of the continental crust and basalt makes up oceanic crust.

Obsidian and PumiceThey are both igneous rocks formed by the quick cooling of lava. Obsidian is from lava that flowed and pumice was violently ejected from a volcano.

Sand, Sandstone and ConglomerateThe sand is sediment that has formed into the sedimentary rocks sandstone and conglomerate.