Download Plate_Tectonics - Hewlett

Plate Tectonics- a theory that was born in the late
1960’s that combines the ideas of continental drift and
sea-floor spreading
 Sea-floor spreading- states that the sea floor is
forming out of the mid-ocean ridges and moves
away from the ridge
*Youngest rocks are in the center of the oceans,
near the mid-ocean ridges.
*Oldest rocks are at the edges of oceans, away from
the mid-ocean ridges, near trenches.
*Supported by the Magnetized Stripes found on
the sea-floor.
The sea floor moves like slow conveyor belts in opposite
directions away from the mid-ocean ridges.
Ocean crust is born at the ridges and dies in the trenches.
Convection Currents in the mantle are responsible for the
moving plates.