Plate Tectonics

What is it? And what makes it work?

Our Earth Not a solid ball of rock Composed of distinct layers Three main layers based on

composition: Crust Mantle Core

The lightest materials make up the outer layers.

The densest materials make up the inner layers.

Let’s Review …

Layers of the Earth

Outermost layer of the Earth. Two types of crust

Continental Less dense than oceanic crust. Contains the Earth’s continents.

Oceanic Found primarily under the ocean. Most dense type of crust.

Crust

Layer between the crust and the core.

Flows very slowly.

Mantle

The innermost part of the earth. Very dense. Composed of iron and nickel. About the size of the planet Mars.

Core

Outermost rigid layer. Made of 2 parts: the crust and rigid

upper part of the mantle. Divided into pieces called tectonic plates.

Lithosphere

There are approximately 30 plates on the Earth’s surface.

The plates move on a layer of rock that is so hot it flows, even though it remains solid.

The plates are moving at speeds up to 10 cm per year.

Plate Tectonics

The force responsible for plate movement.

Convection Currents

Plate Boundaries

Divergent Boundary – move _____

Convergent Boundary – move _____________

Transform Fault Boundary – move ___________________

apart

together (collide)

sideways past each other

Places where two plates move apart or diverge.

Divergent boundaries of two continental plates creates a ________. Example: Great Rift Valley of Africa

Divergent boundaries of two oceanic plates creates a _____. Example: Mid-Atlantic Ridge

Divergent Boundary

rift valley

ridge (sea-floor spreading)

Divergent Boundary

Places where two plates come together, or converge.

Convergent boundaries of two continental plates creates _________. Example: Himalaya Mountains

Convergent boundaries between a continental plate and an oceanic plate forms a __________________ and a ______. This process is called ___________. Example: Coast of Chile

Convergent Boundary

mountains

trenchsubduction

volcanic mountain range

Continent - Continent Plates

Continent – Ocean Plates

Convergent boundaries of two oceanic plates creates ________ and a _____. Example: Islands of Japan

Ocean – Ocean Plates

island arc

trench

Places where two plates slip past each other, moving in opposite directions. Example: San Andreas Fault in California

Transform Boundary

Places where plates move apart are called ________ boundaries.

When continental plates diverge a ________ is formed.

When two oceanic plates converge a ___________________ is formed.

The force moving the plates is _________ . ________ is the process where a denser

______ plate slides under a ________ plate.

Let’s Review…

divergent

rift valley

an island arc and a trench convectio

nSubductionocean

continent