Sea Floor Spreading Centers

Mantle convection is the slow churning motion of earth s mantle.

Sea floor spreading centers.

Spreading center definition a linear zone in the sea floor along which magma rises and from which adjacent crustal plates are moving apart. Seafloor spreading and other tectonic activity processes are the result of mantle convection. The life cycle of the seafloor lesson plan by ashlee henig and stephen halpern. Spreading centers occur at the boundary between two plates that are moving apart called divergent plate boundaries.

Convection currents carry heat from the lower mantle and core to the lithosphere. Seafloor spreading theory that oceanic crust forms along submarine mountain zones and spreads out laterally away from them. Spreading centres are divided into several geologic zones. This is a schematic diagram of a spreading ridge.

Here the plate motion opens a gap between the plates and magma from the mantle rises up through it. This idea played a pivotal role in the development of the theory of plate tectonics which revolutionized geologic thought during the last quarter of the 20th century. It is 1 to 2 km 0 6 to 1 2 miles wide and is the site of recent and active volcanism and of the hydrothermal vents it is marked by chains of small volcanoes or volcanic ridges. The key thing to focus on is the geometry of how the spreading center is offset by a linear feature that is roughly perpendicular to the spreading center.

It is the mid ocean ridges. Seafloor spreading occurs at spreading centers distributed along the crests of mid ocean ridges. Beginning with early evidence of continental drift such as the fit of landmasses and. This 9 block day lesson plan leads students through the discovery of plate tectonics in much the same way scientists learned about it in the 1960 s.

Convection currents also recycle lithospheric materials back to the mantle. Where are most seafloor spreading centers located. When the magma reaches water at the ocean floor most spreading centers are in the ocean it cools and hardens and becomes new. Spreading centers end in transform faults or in overlapping spreading center offsets.

There is more information here than you need for this exercise. The portion that links to the two ridges is the transform fault see also the above diagram and. 2013 12 18 19 39 33 2013 12 18 19 39 33. Adjacent to the neovolcanic zone is one marked by fissures in the seafloor.