Tectonic Plate Boundary Review:

What is Seafloor Spreading? A process that forms a new seafloor... Convection Cell Convection Cell Mantle Mantle Magma rises up on the ocean floor where it splits apart, this makes new ocean floor.

Seafloor Spreading occurs at mid-ocean ridges, These are divergent boundaries

Where is the youngest oceanic crust located? In the center of the ridge...

The youngest oceanic crust is in the center at mid oceanic ridges The older oceanic crust is near the continents at subduction zones The ages of the ocean floor “mirror” each other from the center

Does the center of the ridge always show the current magnetic orientation of the north and south poles? Yes, the current magnetic orientation is indicated at the center. But, in the past, our compass needles pointed to the magnetic South, before that they pointed to the magnetic North, this is a cycle. Magnetic iron in the lava points North or South. Lava forms bands of rocks on both sides of the mid-ocean ridge. They record periods of magnetic reversals N N

Convection Currents in the Mantle