Sea Floor Spreading

 

Sonar

Sound waves used to explore ocean floor

Discovered mid-ocean ridge

 

mid-ocean ridge

 

Theory of Sea Floor Spreading

Where sea floor is spreading apart

 

Harry Hess

Explains continental drift (Wegener was right)

Convection currents

Magma rising up through mantle-

Splits crust apart- new seafloor

 

Evidence

 

 

Sea floor spreading

Youngest rocks near mid-ocean ridge- get older farther away

Magnetic reversals

 

Pushes continents away from each other