the layers of earth and plate tectonics. how do we know what the earth is made of?

The Layers of EarthThe Layers of EarthAnd And

Plate TectonicsPlate Tectonics

How do we know what the How do we know what the Earth is made of?Earth is made of?

How do we know what the How do we know what the Earth is made of?Earth is made of?

• Geophysical surveys: seismic, gravity, magnetics and electrical

Earth LayersEarth Layers

• The Earth is divided into four main layers.

*Inner Core*Outer Core*Mantle *Crust

The CrustThe Crust• The Earth’s crust is

like the skin of an apple. It is very thin compared to the other three layers.

• *The crust makes up 1% of the Earth.

* The crust of the Earth is broken into many pieces called plates.

The MantleThe Mantle• The mantle is

the layer below the crust.

• The mantle is the largest layer of the Earth.

• The mantle is divided into two regions: the upper and lower sections.

Outer CoreOuter Core•The core of the

Earth is like a ball of very hot metals.

* The outer core is liquid.

* The outer core is made up of iron and is very dense.

Inner CoreInner Core* The inner core of

the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move.

* The inner core is a solid.

LithosphereLithosphere

• The lithosphere 

consist of the crust plus the very upper part of the mantle

AsthenosphereAsthenosphere

• Layer of the mantle directly below the Lithosphere.

• Upper Mantle that is soft and bendable like plastic (but still solid).

ReviewReview1) What are the four layers of the

Earth?

2) The Earth’s crust is very ______?

3) The mantle is the largest layer of the Earth? True or False

4) Is the Outer Core a liquid or a solid?

Answers!Answers!

1) Crust, Mantle, Outer Core, Inner Core

2) Thin3) True4) Liquid

Plate TectonicsPlate TectonicsIf you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

Plate TectonicsPlate Tectonics•The Earth’s crust is divided

into 12 major plates which are moved in various directions.

•This plate motion causes them to collide, pull apart, or scrape against each other.

•The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.

Plate TectonicsPlate Tectonics

• How Plates Move

Earth’s Lithospheric Earth’s Lithospheric PlatesPlates

Three types of plate boundaryThree types of plate boundary

• Divergent

• Convergent

• Transform

• Plate Tectonics in Action Video

Divergent BoundariesDivergent BoundariesThis map shows the age of the oceanic crust. The red coloring shows the youngest ages, while the dark blue shows the oldest ages (around 200 million years old). The divergent boundary runs

straight through Iceland….

Divergent BoundariesDivergent Boundaries

• Spreading ridges

–As plates move apart new material is erupted to fill the gap

Convergent BoundariesConvergent Boundaries

• There are three styles of convergent plate boundaries

1. Continent-continent collision

2. Continent-oceanic crust collision

3. Ocean-ocean collision

Continent-continent Continent-continent Collision make mountainsCollision make mountains

Himalayas

Continent-Oceanic Crust Continent-Oceanic Crust CollisionCollision

Also called subduction form volcanoes

Ocean-Ocean Plate CollisionOcean-Ocean Plate Collision

• Forms deep ocean trenches

Mariana Trench is 11km deep!

Transform BoundariesTransform Boundaries

Where plates slide past each other

San Andreas Fault

Color Code Plate BoundariesColor Code Plate Boundaries

• You will need this map to complete future assignments