Plate Tectonics

Plate

Tectonics

Earth Alive

Plate Tectonics

• Theory that states the Earth’s crust is

made of plates that are moving.

• Plates move rafts that float.
• The mantle is part of the Earth’s

interior located beneath the crust.

• Movement of material inside the mantle

causes the plates to move.

• That material is called magma!

Multiple Choice

True or False: The theory of plate tectonics states the Earth's crust is made of plates that are moving.

• True

• False

Convection Currents

• The magma in the

mantle moves in
currents. The hot
magma will rise
toward the surface
and the cooler magma
will sink.

• This movement causes

the Earth’s crustal
plates to move.

Multiple Choice

Where do convection currents occur?

• Core

• Crust

• Mantle

• Space

Multiple Choice

What causes Earth's plates to move?

• Continental Drift

• Convection Currents

• Dinosaur bones melting

• Plate tectonics

Continental Drift

• Alfred Wegener- Continental drift

IDEA!!

• Continental drift-continents have moved

slowly to their current location but
didn’t explain how.

• Pangaea- “all land”…name given to single

large landmass that was 200 million
years ago.

Multiple Choice

What do we call the large landmass that was made up of all of the continents?

• North America

• Paris

• Pangea

• Ocean

Evidence of Continental Drift

• Fossil clues
• Climate clues

– Warm weather

plants now found
in colder climates

• Rock clues

– Rock composition
and structure

Seafloor Spreading

• Hot, dense material below Earth’s crust

rises toward the surface.

• This movement causes a mid-ocean ridge

on the sea floor.

• The hot magma causes the plates to

move (or diverge) moving the sea floor
in opposite directions.

Mid-Ocean Ridge

• The mid ocean ridge is the location of

“new Earth” material.

• The magma will cool and form new

crust.

Multiple Choice

Where can you find the youngest crust?

• Under a mountain

• At the mid ocean ridge

• On a convergent boundary

• At at transform boundary

Earth’s Plates

Parts of Earth’s plates:

1.

lithosphere: rigid layer; usually less dense
than the layer beneath it.

2.

Asthenosphere: plastic like layer under
the lithosphere

The rigid plates of the lithosphere
are on top of the plastic like
asthenosphere and move because of
convection currents.

Multiple Choice

Which part of Earth's plates would be described as plastic like?

• Core

• Lithosphere

• Asthenosphere

• Crust

Plate Boundaries

• Movement at plate boundaries cause

changes to Earth’s surface.

• Types of Plate Boundaries:

– Divergent boundaries
– Convergent boundaries
– Transform boundaries (aka strike-slip)

Divergent Boundaries

• When 2 plates move

apart.

• Can form a rift valley

when 2 continental
plates are spread
apart.

• A mid-ocean ridge

can form where
oceanic plates
separate.

• As the magma moves

up, new oceanic crust
is formed.

East

African

Rift
Valley

Multiple Select

What forms at divergent boundaries?

• Mid ocean ridges

• Rift Valley

• Mountains

• Waves

Convergent Boundary

• When 2 plates collide or move together.
• When 2 oceanic plates collide, one plate

can move underneath another plate.

• This area is called a subduction zone and

can form volcanoes.

• Mountains can also form where

continental plates collide.

Mountains & Volcanoes

Transform Boundary

• Also called Strike-slip fault
• Plates can move in opposite directions or

the same direction.

Multiple Choice

At which boundary type do the plates collide

• Divergent

• Convergent

• Transform

Multiple Choice

At which boundary type do the plates slide by each other

• Convergent

• Divergent

• Transform