COOLING

WEATHERING, EROSION,AND DEPOSITION COMPACTION AND

CEMENTATION

HEAT ANDPRESSURE

MELTING

THE ROCK CYCLE

WEA

THER

ING,

ERO

SION,

AND D

EPOSI

TION

MELTED ROCK

IGNEOUS ROCK

SEDIMENT

SEDIMENTARY ROCK

METAMORPHIC ROCK

The Rock CycleThe Rock Cycle• The Earth is constantly changing. Even the very rocks

around you may have changed many times throughout their history!

• The Rock Cycle explains the evolution of these igneous, sedimentary, and metamorphic rocks that make up the Earth’s crust.

• Many processes, such as volcanic activity, movement of the crust, and erosion and deposition of rocks on the surface, create different environments where various types of minerals and rocks form.

Let’s take a ride on the Rock Cycle!Back to the beginning

Melting…

MELTED ROCKMELTED ROCK• Generally appears atplate boundaries when crustal plates are colliding or spreadingapart.

• Magma forms beneaththe surface.

• Lava is found on thesurface.

Go back to the Rock Cycle Cool this melted rock!

Magma

Lava

Cooling…Cooling…

IGNEOUS ROCKSIGNEOUS ROCKS

• Form as melted rock cools.

• Can be extrusive or intrusive.

• Examples include granite, basalt, and obsidian.

Go back to the Rock Cycle

Choose your own Adventure:

Add some heat and pressure!

Weather and erode this rock!

WEATHERING AND EROSIONWEATHERING AND EROSION• Did you know that the sand on the beach used to be part of

a rock?

• Once a rock is made, it doesn’t stay that way! If it is on the surface, the rock is broken down into sediments by weathering processes, then moved to a new location by erosional forces.

• Weathering is the process of decomposition or disintegration of rocks in place.

• Erosion is the movement of weathered materials by water, wind, ice, or gravity.

Go back to the Rock Cycle Deposit sediment

SEDIMENTSSEDIMENTS

• Sediments are mineral or organic particles that are deposited by the action of wind, water, ice, or gravity.

• Boulders, gravel, sand, and mud are all types of sediments.

Go back to the Rock CycleCompact and cement these sediments!

SEDIMENTARY ROCKSSEDIMENTARY ROCKS•As the sediments settle, they compact.

•If the sediments are small enough, they can form rocks.

•If the sediments are large, natural cements fill in the empty spaces and “glue” the sediments together.

Choose your own Adventure:

Weather and erode this rock!

Add heat and pressure to this rock!

Go back to the Rock Cycle.

Examples of sedimentary rocks include sandstone, shale, and limestone.

METAMORPHIC ROCKSMETAMORPHIC ROCKS• These rocks have gone through a

lot!

• Metamorphic rocks form from pre- existing rocks that have changed due to high temperatures, pressures, or chemical changes.

Go back to the Rock Cycle

Choose your own Adventure:

Melt this rock!

Weather and erode this rock!

Examples of metamorphic rocksinclude gneiss, slate, and marble.

GLOSSARYGLOSSARY• Cement: A substance that hardens to act as an

adhesive; glue.• Compact: become pressed together• Erosion is the movement of weathered materials

by water, wind, ice, or gravity.• Extrusive: an igneous rock formation

environment that occurs on the surface • Intrusive: an igneous rock formation environment

that occurs beneath the surface• Lava: molten rock on the Earth’s surface • Magma: molten rock beneath the Earth’s surface• Weathering is the process of decomposition or

disintegration of rocks in place.

Take me back to the Rock Cycle!

GraniteGranite

•Intrusive igneous rock.

•Cools slowly and has large crystals.

•Generally found on the continents.

Go back to Igneous Rocks

BasaltBasalt

• Extrusive igneous rock

• Cools quickly and has small crystals.

• Oceanic crust is made up of basalt.

Go back to Igneous Rocks

ObsidianObsidian

• Often called “volcanic glass”

• Extrusive igneous rock that cools extremely quickly.

• Does not have crystals.Go back to Igneous Rocks

SandstoneSandstone

•A sedimentary rock consisting of quartz sand cemented together by other minerals.

•May be many colors, including grey, yellow, red, and white.

•Is capable of holding large quantities of water.

Go back to Sedimentary Rocks

ShaleShale

• Formed from clay and mud particles that have been pressed into thin sheets.

• Extremely fine-grained material

Go back to Sedimentary Rocks

LimestoneLimestone

• Generally forms from calcite produced by marine organisms, and may contain fossils.

• May also form from groundwater containing dissolved calcite.

• Will “fizz” when in contact with hydrochloric acid (HCl).

Go back to Sedimentary Rocks

GneissGneiss

• A coarse-grained rock with bands of light colored minerals that alternate with bands of dark-colored minerals.

• Similar in composition to granite (quartz, feldspar, mica)

Go back to Metamorphic Rocks

SlateSlate

• Fine-grained rock composed of metamorphosed clay or volcanic ash.

• Generally forms when shale undergoes metamorphism.

• Has distinctive layers.

Go back to Metamorphic Rocks

MarbleMarble

• Metamorphosed limestone

• Often used in sculpture and as a building material

• Does not have layers or bands

Go back to Metamorphic Rocks