EARTH'S DYNAMICS

The Earth’s Crust Four layers of the Earth: Core: the solid inner core of the Earth Outer core: liquid core rich in iron Mantle: partly solid partly molten magma Crust: thin, rigid crust of land

The Earth’s Crust

Plate Tectonics The Earth’s crust is divided into rigid, slow moving plates The plates are floating on the Earth’s mantle Plates move with the current of magma The movement of these plates build mountains and valleys

The Theory of Plate Tectonics The “theory of plate tectonics” was developed by a German Scientist named Alfred Wegener He was a polar researcher, geophysicist and meteorologist. His hypothesis was controversial and not widely accepted until the 1950s

World Plates

Forces Beneath the Crust The Current of the magma moves the Earth’s Crust Volcano: opening in the crust of the Earth where lava flows Movement of magma can break or bend the crust Fold: layers of rock are folded Fault: layers of rock break (cause of earthquakes)

PLATE BOUNDRY ZONES

Plate Boundaries / Zones Three types of plate boundaries: Divergent: plates moving away from each other Convergent: plates moving towards each other Conservative (transform): plates sliding past each other

Divergent Mid Atlantic Ridge is an example of divergent forces or sea-floor spreading                                             

Convergent Subduction Zone: a tectonic plate collides with another plate forcing the lighter plate into the mantle

Conservative (Transform)     Faults slip past each other causing earthquakes                                            

CONTINENTAL DRIFT

Continental Drift 200 million years ago, the continents were locked together in a single land mass called Pangea Pangea broke into two supercontinents named Laurasia and Gondwanaland

EROSION

Erosion Erosion is the wearing away of land Rock weathering: the process that breaks up rock (sediment is small particles of rock) Water: most powerful force of erosion (V- canyons and U-canyons)

Erosion Continued.. Wind: transports light sediment Glaciers: sheet glaciers: ice sheets that cover large areas pressing outwards Mountain glaciers: small ice sheets covering mountains flowing downhill