Plate tectonics axb

The interior structure of the earth

The interior structure of the earth

• The crust and part of the upper mantle = lithosphere– about 100 km thick –Less dense than the material below

it so it “floats”

The interior structure of the earthThe Lithosphere

• The plastic layer below the lithosphere = asthenosphere

• The plates of the lithosphere float on the asthenosphere

The interior structure of the earthThe Asthenosphere

• Two types of crust:

•Continental•Oceanic

The interior structure of the earthThe Crust

• Differences between oceanic crust and continental crust?

• Continental crust is composed of granite while the oceanic crust is composed of basalt.

• The density of the continental crust is less than the oceanic crust, thus it floats higher on the mantle.

How this tears the surface apart

In 1912 a German scientist named Alfred Wegener proposed the theory that the crustal plates are moving over the mantle. This was supported by fossil and rock type evidence; also matching of coastline shapes.

Pangaea

The Spreading Continents

Plate Boundaries Map

Major plates only

Plate Boundaries Map

Types of Plate Boundaries

Types of Plate Boundaries

Rift Valleys - ccd

Oceanic Convergence

Oceanic to Continental Convergence

Continental Collision

Transform Faults

The future?