Causes Sea Floor Spreading

3 magnetic reversals and sea floor spreading.

Causes sea floor spreading.

Seafloor spreading is a geologic process in which tectonic plate s large slabs of earth s lithosphere split apart from each other. Sea floor spreading is caused by a ridge opening in the earths crust where new magma lava rises up and adds to the sea floor. As each new centimeter is added and cools another takes its place. Mantle convection is the slow churn ing motion of earth s mantle.

What causes sea floor spreading. Describe the process that causes bands of different magnetic orientation on the seafloor. This is sea floor. Seafloor spreading and other tectonic activity processes are the result of mantle convection.

On the basis of tharp s efforts and other new discoveries about the deep ocean floor hess postulated that molten material from earth s mantle continuously wells up along the crests of the mid ocean ridges that wind for nearly 80 000 km 50 000 miles through all the world s oceans. In the 1960s a geologist named harry hess was able to show how the seafloor spread when magma rose to the surface. Why was it important for the theory of seafloor spreading that these bands were symmetrical on each side of the. When the divergent boundary spreads it caues a mid ocean ridge.

The seafloor spreading hypothesis was proposed by the american geophysicist harry h. A younger oceanic crust is then formed causing the spread of the ocean floor. He demonstrated that the ridges in the middle of the great oceans were the result of magma breaking through creating a divergent boundary where the seafloor spread apart. The new rock is dense but not as dense as the old rock that moves away from the ridge.

Sea floor spreading is caused by convection currents in the mantle to cause a divergent boundary underwater. The process of continental drift now better known as plate tectonics is driven by creation of new ocean crust at sea floor spreading sites like the mid atlantic ridge and east pacific rise and compensatory mechanisms of lithospheric subduction. When the molten magma reaches the oceanic crust it cools and pushes away the existing rocks from the ridge equally in both directions. What is actually happening to the magnetite in the molten rock as it emerges onto the seafloor.

This is how new oceanic crust is created.