The Crust Under The Ocean Floor

The continental crust covers only one third of the earth s surface and makes up all of the dry land found on earth.

The crust under the ocean floor.

Magma oozes up from the mantle through a crack in the ocean floor filling in the space between the plates and spreading out from the plate boundary. The crust under land is thicker and contains more rock types. The oldest existing oceanic crust is in the ionian sea part of the eastern mediterranean basin. The oceanic crust displays a pattern of magnetic lines parallel to the ocean ridges frozen in the basalt.

Subduction zone the place where one plate is getting bent and pulled under the edge of another plate. Oceanic crust is about 6 km 4 miles thick. Largely due to subduction oceanic crust is much much younger than continental crust. The destruction of oceanic crust occurs at subduction zones where oceanic crust is forced under either continental crust or oceanic crust.

Structure of the earth. A symmetrical pattern of positive and negative magnetic lines emanates from the mid ocean ridge. Oceanic crust is thin and young no more than about 20 km thick and no older than about 180 million years. The crust thickness averages about 18 miles 30 kilometers under the continents but is only about 3 miles 5 kilometers under the oceans.

Plate tectonics plate tectonics seafloor spreading. Everything older has been pulled underneath the continents by subduction. Two types of crust make up the land on earth and its ocean floor. It is composed of several layers not including the overlying sediment.

Oceanic crust covers about 60 percent of the earth s surface. Oceanic crust the outermost layer of earth s lithosphere that is found under the oceans and formed at spreading centres on oceanic ridges which occur at divergent plate boundaries. Today the atlantic basin is actively spreading at the mid atlantic ridge. It is light and brittle and can break.

Only a small portion of the oceanic crust produced in the atlantic is subducted. New rock is formed by magma at the mid ocean ridges and the ocean floor spreads out from this point. The oldest parts of continental crust on the other hand are more than 4 billion years old. The seafloor of the ionian sea is about 270 million years old.

Samples collected from the ocean floor show that the age of oceanic crust increases with distance from the spreading centre important evidence in favour of this process. These age data also allow the rate of seafloor spreading to be. Oceanic crust is born at the mid ocean ridges where plates are pulled apart.