Oceanic vs Continental Crust
The outermost layer of the Earth, the crust, covers the planet. The crust floats upon the molten mantle. Its constitution is not the same throughout. Accordingly, the crust is divided into two types; the continental crust and the oceanic crust.
Oceanic Crust
The oceanic crust is that part of the Earth’s crust that covers the ocean basins. It consists of dark-colored rocks made up of basalt. This rock is made up of silicon, oxygen, and magnesium.
The density of the oceanic crust is about 3.0 g/cm3. The continental crust has a lower density. This difference in the average densities allows many natural phenomenon to occur on and below the surface of the Earth. The oceanic crust scarcely floats on the mantle.
The oceanic crust undergoes a peculiar phenomenon. With age, the oceanic crust gathers a layer of cooled mantle on the underside. This causes the two-layered structure to sink into the hot, molten mantle. Once in the mantle, the oceanic crust melts and is thus recycled. Due to this process there is an absence of aged oceanic crust. This phenomenon is absent or rare in the continental crust.
The thickness of both the crusts also varies. For the oceanic crust, the thickness is around 3 to 6 miles which is about 5 to 10 kilometers. The oceanic crust is thinner than the continental crust.
Continental Crust
The continental crust accounts for 40% of the surface of the Earth. It is made up of granite rock which is light in color. This rock is rich in constituents like silicon, aluminum, and oxygen.
The density of the continental crust is much less as compared to the oceanic crust. It has an approximate value of 2.6 g/cm3. Due to this difference in densities in magma between the oceanic crust and the continental crust, the continents stay in their places, and both crusts are able to float on the magma. The continental crust floats much more freely on the magma.
The continental crust is much thicker when compared to the oceanic crust. It has a thickness ranging from 20 mi., which is about 35 km., on the plains, to as much as 40 mi., which is about 70 km., on the highest mountains.
Summary:
1.The oceanic crust is made up of basalt while the continental crust is made up of granite.
2.The oceanic crust is thinner while the continental crust is much thicker.
3.The oceanic crust is denser than the continental crust.
4.The continental crust has greater buoyancy than the oceanic crust.
5.Recycling is present in the oceanic crust while this procedure is absent in the continental crust.
6.The oceanic crust is much younger geologically than the continental crust.