Earth’s Interior and Plate

Tectonics

Physical Science

Section 17.1

This is how the continents

formed….

• http://www.youtube.com/watch?v=TzzGPf

Vx32M&list=PLABDC7B24FAFE33FD

The Earth is like a parfait, it has layers

• If you cut the earth in half, it would look

very much like a parfait, with different

layers and compositions based on density

• The earth has three main layers, the crust,

the mantle, and the core

The Crust

• We live on this layer

• Its is cool, and made of

solid rock

• Oceanic crust is thinner

and denser than

continental crust.

• The crust is the least

dense portion of the earth

and only about 12-25

miles thick

The Mantle

• Layer of rock that is

denser than the crust

• About 1800 miles thick

• Outer mantle is solid rock

• Inner mantle the rocks

are extremely hot and

bendable like gum

(plastic)

The Core

• The center of the earth

• Made mostly of iron and nickel

• The inner core is solid metal while the

outer core is liquid metal

The Earth heats up with depth

• At only 2 miles down the temperature

increase to 120 F

• The core is much hotter than the mantle

• In the core, temperatures reach over

10,000 F

The earth heats up with depth

• The earth gets warmer towards the core

because it contains so many radioactive

isotopes

• These unstable isotopes are constantly

breaking down, releasing huge amounts of

energy, which in turn heat the earth

How do plates move?

http://www.youtube.com/watch?v=ryrXAGY1dmE

Evidence #1:

The Pangea Puzzle • In the 20th century, Alfred

Wegener noticed that eastern S.America fits into western Africa

• He also noticed that several of the other continents fit together like puzzle pieces

• He also found that fossil evidence showed that several of the same organisms are found on continents now separated by oceans

• He theorized that 250 million years ago all the continents combined to form the giant land mass he named pangea

How did this happen?

• The earth’s outer shell, called the

lithosphere is made of the crust and upper

portion of the mantle.

• This lithosphere is very rigid and consists

of 7 large pieces and a few small ones that

fit together like a puzzle

• These large pieces are called tectonic

plates

Plate Tectonics • These plates fit together like puzzle pieces and

move in relation to each other

• these plates move away, towards, or alongside

each other

• Tectonic plates move about 6 inches per year

Divergent Plate Boundaries

• In some areas, the plates move away from

each other

• When this occurs, hot liquid rock called

magma rises and cools, forming new

lithospheric rock

Convergent Plate Boundaries

• Less dense continental plate floats over more dense oceanic plate

• This process is called subduction

• As this more dense rock goes down into the mantle, it heats up and melts

• The magma rises and pushes up the crust, forming volcanic mountains also earthquakes

• Subduction - two plates meet, the more

dense plate (oceanic crust), dives beneath

the less dense plate (continental crust)

Continental vs. Continetal

• Same density

so no

subduction

• Builds non-

volcanic mts.

• Earthquakes

Oceanic vs. Oceanic

• Similar

density, but

subduction

anyway

• Earthquakes,

trenches,

• volcanic

island arcs

Transform Fault Boundaries

• These are areas where plates move along side one another

• As plates move, they can cause cracks in the lithosphere called faults

• As plates move along side each other at these faults, the plates cause a great deal of force and create earthquakes

RECAP

• Divergent Plate Boundaries – Divergent means plates MOVE AWAY from

each other

• Convergent Plate Boundaries – Convergent means plates MOVE TOWARD

each other

• Transform Fault Boundaries – areas where plates move along side one another

• like this or this

•

• Earth is made of 3 main layers

– Crust- cool, thin, made of rock, 10-25 miles

thick

– Mantle, denser than crust, 2500 miles thick,

80% of earth’s volume: inner mantle solid

rock, outer mantle bendable gummy rock

– Core- center of earth, made of iron and nickel,

made of 2 layers: inner solid metal, outer

liquid metal

• Pangea- 250 million years ago all the

continents combined to form the giant land

mass called Pangea

• Lithosphere (earth’s outer shell) is made of

the crust and upper portion of the mantle.

• lithosphere -very rigid and consists of 7

large pieces (called tectonic plates) and a

few small ones that fit together like a

puzzle

• Plate Tectonics

• These plates fit together like puzzle pieces

and move in relation to each other

• these plates move away, towards, or

alongside each other

• Tectonic plates move 6 inches per year

Evidence 2:

Biogeographical

Final views

• http://www.youtube.com/watch?v=QrQDX

nnXOo4&feature=player_embedded#!