Sea floor spreading causes this. As the floor spreads apart new magma is being pushed up through the ridge from the mantle through convection currents. It's like a recycling system.
the ridges
It was created on the sea floor.
antartica
Seafloor Spreading created by harry hess
At Mid-Ocean Ridges.
New sea floor is being created at mid oceanic ridges.
the divergent plate boundary is the one that is sea floor created
sea-floor spreading
Seafloor Spreading created by harry hess
the sea floor separates. magma comes up the crack forming new sea floor
Forms by lava from volcanoes on the sea floor
Sea Floor Spreading!