PRESENTATION OUTLINE
PLATE TECTONICS
Pieces of Earth's lithosphere are in slow, constant, motion, driven by convection currents in the mantle
ONE CAUSE OF PLATE TECTONICS
The main source is convection currents in the mantle. (Mantle Convection)
SECOND CAUSE OF PLATE TECTONICS
Gravity pulling on the plates in the subduction zone also helps move them. (Slab Pull)
THIRD CAUSE OF PLATE TECTONICS
The third cause is sea-floor spreading. New crust forming pushes the tectonic lattes apart. (Ridge Push)
DIVERGENT BOUNDARY
A boundary where plates are moving apart.
DIVERGENT BOUNDARIES RESULTS
Divergent boundaries form a Rift Valley when they occur on land.
DIVERGENT BOUNDARIES RESULTS
Divergent boundaries form mid-ocean ridges when they occur underwater.
CONVERGENT BOUNDARY
The place where two plates collide (converge).
CONVERGENT BOUNDARY RESULTS
When ocean crust collides with continental crust, a deep ocean trench forms. (Peru-Chile Trench)
CONVERGENT BOUNDARY RESULTS
When two oceanic plates collide, trenches with island arcs or underwater volcanic arcs form. (Kril Islands)
CONVERGENT BOUNDARY RESULTS
When two pieces of continental crust collides, mountain ranges form. (Himalayas)
SUBDUCTION ZONE
Subduction is the process by which ocean crust sinks beneath a deep ocean trench and back into the mantle.
DEEP OCEAN TRENCH
A trench is the result of oceanic crust being subducted into the mantle.
DEEP OCEAN TRENCH
An example of a deep ocean trench is the Puerto Rico Trench.
TRANSFORM BOUNDARY
A place where two plates slip past each other, moving in opposite directions.
TRANSFORM BOUNDARY RESULTS
Earthquakes happen here, but no crust is created or destroyed.
TRANSFORM BOUNDARY RESULTS
An example of a Transform boundary is the Alpine Fault of New Zealand.
