PLATE TECTONICS

PLATE TECTONICS

• Pieces of earths lithosphere are in slow constamt motion driven by convection currents in the mantle
• The motion of the plates cause earthquakes, mountain building and volcanic activity

WHAT FORCES MOVE THE PLATES

• The main source is convection currents in the mantle
• Gravity pulling on the plates in the subduction zone also helps them move
• Seafloor spreading - when new crust forming pushes the tectonic plates apart

DIVERGENT PLATE BOUNDARY

• A boundary where plates are moving apart
• A mid ocean ridge is an example of in the ocean
• A Rift Valley is an example of on land

CONVERGENT BOUNDARY

• The place where two plates converge
• When ocean crust collides with Continential crust a deep ocean trench forms
• When two continental plates collide, mountains form

SUBDUCTION ZONE

• When one plate sinks into the mantle underneath the other

DEEP OCEAN TRENCH

• any long, narrow, steep-sided depression in the ocean bottom
• form in locations where one tectonic plate subducts under another.
• The Mariana Trench is an example

TRANSFORM PLATE BOUNDARY

• Transform boundaries are places where plates slide sideways past each other
• At transform boundaries lithosphere is neither created nor destroyed.
• San Andreas fault is a transform boundary.