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 the ocean floor.
As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading.
It is composed of several layers not including the overlying sediment.
The destruction of oceanic crust occurs at subduction zones where oceanic crust is forced under either continental crust or oceanic crust.
The oldest parts of continental crust on the other hand are more than 4 billion years old.
Continental crust earth.
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.
The continental crust covers only one third of the earth s surface and makes up all of the dry land found on earth.
Subduction zone the place where one plate is getting bent and pulled under the edge of another plate.
The oceanic crust displays a pattern of magnetic lines parallel to the ocean ridges frozen in the basalt.
Two types of crust make up the land on earth and its ocean floor.
Oceanic crust is born at the mid ocean ridges where plates are pulled apart.
A symmetrical pattern of positive and negative magnetic lines emanates from the mid ocean ridge.
It is light and brittle and can break.
New rock is formed by magma at the mid ocean ridges and the ocean floor spreads out from this point.
Oceanic crust is about 6 km 4 miles thick.
Plate tectonics plate tectonics seafloor spreading.
Oceanic crust covers about 60 percent of the earth s surface.
The crust under land is thicker and contains more rock types.
Everything older has been pulled underneath the continents by subduction.
The seafloor of the ionian sea is about 270 million years old.
The oldest existing oceanic crust is in the ionian sea part of the eastern mediterranean basin.
Structure of the earth.
These age data also allow the rate of seafloor spreading to be.
Only a small portion of the oceanic crust produced in the atlantic is subducted.
The process that forms new ocean floor and oceanic crust.
Largely due to subduction oceanic crust is much much younger than continental crust.
Today the atlantic basin is actively spreading at the mid atlantic ridge.