Rocks

Three Types of rock

• Igneous• Metamorphic• Sedimentary

Three totally different types of rock that all basically come from the same

materials

Q: So how do we get such different rocks?

Igneous Rocks?

Metamorphic Rocks?

Sedimentary Rocks?

They all look and act so differently, how do they all form?

A: The Rock Cycle!!!

Metamorphic Rocks

Igneous Rocks

Sedimentary Rocks

can become

can beco

mecan becomeMain Concept: Any rock type can be changed

into any of the other two and back again through the Rock Cycle depending on conditions

The process of rocks changing from The process of rocks changing from one type of rock to anotherone type of rock to another

Molten material comes from volcanoes

Igneous Rocks

The type of igneous rock depends on how fast it cooled!

All Igneous rock comes from molten material

How to get Igneous Rocks:

Melting of Material

Cooling Magma Explosive VolcanismCan you see the big differences in these two rocks?

Large Crystals Lots of holes

Is made from cooled magma down here

Is made from exploding material up here

Weathering• If rocks are exposed at the surface; they are exposed to the

elements in the air.• All the “elements”: rain, wind, animals, plants, ice and even simply

a release of pressure can cause the chemical bonds in rocks to break apart.

• The process of breaking the bonds in rock and making it “softer” is called: Weathering!

Erosion

• After a rock has been weathered, it is easy to break.• If a rock breaks into pieces it becomes easier to move from one

place to another.• The movement of rock pieces and or soil from one place to

another by natural processes is called: Erosion!

The cliff is slowly falling down! The pile of sediments here used to be part of this cliff!

Sedimentary Rock =cemented sediments

The sand here is loose and not cemented together

This Sandstone in Utah is made from sand that has been cemented together

Can you see the different layers of sand?

Sedimentary Rock Recipe 1. Start at the

Surface

4. Sedimentation & Deposition

5. Compaction & Cementation

2. Weather (Break Up)

3. Erode (Carry Away)

© Beadle, 2009

Sediments worn away gather here!

Igneous rock

Layers of sand and sedimentsRain moves sand, dirt, and

rocks down to the ocean

How to get Sedimentary Rocks:

ErosionWeathering Deposition Cementation

Water and pressure helps bond the particles of sediment together

to make a rock

Rocks get broken downby exposure to water,

wind, etc…Broken down sediments

are transported towards the sea and spread out

Broken down rocks fall apart

Weathering(Rock broken down by

exposure to rain, wind, etc..)

Erosion(pieces fall down to

bottom of cliff)

Deposition(smaller pieces are spread

out across area)

Cementation(eventually pieces get

stuck together and becomes a rock)

This is what it looks like in

real life:

Rivers can do a lot of this on their own:

Deposition is taking place when the river

meets the ocean

You can see lots of sediments flowing in the river

You can see lots of sediments spreading out!

Now all that is left are salty rocks that form a dry lake bed

Evaporation:New rocks can be formed when water is evaporated

There used to be a nice deep ocean here

But then the water evaporated…

When the water leaves, the electrons of the chemicals thatWhen the water leaves, the electrons of the chemicals thatmake up the rocks are attracted to each other and cause make up the rocks are attracted to each other and cause clumps of rock to form from the small particles left behind.clumps of rock to form from the small particles left behind.

Limestone is very common in Limestone is very common in the mountains of Utahthe mountains of Utah

Q: Where did this limestone originally come from?

A: Underwater!

Limestone is the remains of sea critters shells that have been compacted together to form rock at the bottom of a sea

Pressure and Heat Lead to Metamorphic Rocks

• Rocks that get buried again can get squished and heated to the point that they change!

This rock is called “Gneiss” (nice).

Q: Can you remember what it has “morphed” from?

A: Granite!!!

If you look closely, you can see the same minerals in both rocks!

The white tops of these mtn’s are granite= Igneous

Erosion is actively breaking down the mountains

(forming canyons!)

Deposition: minerals from the Granite

spreading out as sand! (This makes the soil of the valley)

The rock cycle is an active process that you can see just about everywhere outside:

Underneath all the sand, sediment is being compacted

=Sedimentary

Soil is basically all the small broken up pieces of rocks!Broken down tons of times into smaller

and smaller sediments

***You will need to know the processto make each type of rock!

The Real Rock Cycle

Rock Cycle with illustrations:

Hot Mantle

Cooler Crust Plate motionPlate motion

Convection current Convection current

Q: What rock will we get if two continental plates collide?

Let’s connect the rock cycle with plate tectonics!

Hot Magma

Compression

= Metamorphic

Plate motionPlate motion

Continental plate collides with Continental Plate causing mountains to form!

Cloud will bring falling water

Label where metamorphic, igneous & sedimentary rocks are formed as the numbers appear:

Hot Mantle1

5

6

7

6

6

3 plate motion2

plate motion Earthquakes

4

Volcanic ExplosionExtrusive Igneous Rock

Continental collides with Oceanic:

Divergent Convergent

3

Plate Tectonics Rock Cycle Key: Notice where metamorphic, igneous & sedimentary rocks are processed & formed.

Cloud

SedimentarySedimentaryExtr

usive Ig

neous Extrusive Igneous

Intrusive Igneous

Metamorphic

Intr

usiv

e Ig

neou

s

Met

amor

phic

Metamorphic

Melted rock

Extrusive Igneous

Assessment:Identify where the terms/description on Identify where the terms/description on the left should go in the rock cycle on the left should go in the rock cycle on

the rightthe right

• Heat, Pressure

• Extrusive (Volcanic Eruptions)

• Deposition & Cementation

• Melting• Intrusive

(Cooling & Crystallization)

• Weathering & Erosion