Plate Tectonics

The Crust Outermost layer 5 – 100 km thick Made of Oxygen, Silicon, Aluminum

The Mantle Layer of Earth between the crust and the core Contains most of the Earth’s mass Has more magnesium and less aluminum and silicon than the crust Is denser than the crust

The Core Below the mantle and to the center of the Earth Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium

Pangaea The ancient (225 million years ago) supercontinent that split apart into the continents we know today.

Evidence of Pangaea

Continental Drift The theory used to explain the movement of the continents on earth. It was first proposed by Alfred Wegner less than 100 years ago (1912) animation

How Plates Move: Convection Currents

Plate Boundaries The term “plate boundary” refers to the edges where the different plates on earth are touching. illustration Each of the plates have a name.name

There are Three Types of Plate Boundaries Convergent areas of plates that are moving toward each other animation

Indian and Eurasian Plates Convergent Boundary

Convergent Boundary – Oceanic & Continental

Convergent Boundary – Oceanic & Oceanic

Convergent Boundaries - Continental

There are Three Types of Plate Boundaries Divergent areas of plates that are moving away from each other animation

Divergent Boundary - Oceanic

Divergent Boundary - Continental

Sea Floor Spreading

Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins Magma rises to the surface and solidifies and new crust forms Older Crust is pushed farther away from the ridge

There are Three Types of Plate Boundaries Transform areas of plates that are sliding past each other; results in the largest and most destructive earthquakes image

Transform Boundary – San Andreas Fault

Plate Boundary Locations click image to launch animation

Let’s Review What are the three type of plate boundaries? convergent divergent transform

Let’s Review Which type of plate boundary results in the largest, most destructive earthquakes? transform