What Is the Difference Between Oceanic Crust and Continental Crust?

How is oceanic crust different from continental crust?

The Earth has three different layers to it. The crust is the part of the Earth right on top where people live. The crust is subdivided into two types, oceanic and continental.

Oceanic crust

Oceanic crust is found under oceans, and it is about four miles thick in most places. A feature unique to oceanic crust is that there are areas known as mid-ocean ridges where oceanic crust is still being created. Magma shoots up through gaps in the ocean’s floor here. As it cools, it hardens into new rock, which forms brand new segments of oceanic crust. Since oceanic crust is heavier than continental crust, it is constantly sinking and moving under continental crust.

Continental crust

Continental crust varies between six and 47 miles in thickness depending on where it is found. Continental crust tends to be much older than the oceanic kind, and rocks found on this kind of crust are often the oldest in the world. Examples of such rocks are those in Quebec, Canada which are estimated to be about 4 billion years old.

Comparing the two different kinds of crust.

What is the difference between Oceanic and Continental Crust?

Composition

Oceanic crust is dominated by mafic and ultramafic intrusive igneous rocks whereas continental rocks are dominated by granitic (felsic) intrusive igneous rocks. The mantle, oceanic crust, and continental crust all have different compositions due to a process called partial melting.

Formation

The differences between oceanic crust and continental crust are due to the different ways in which they are formed. Oceanic crust is formed from magma that rises from the mantle and cools at the ocean floor. Continental crust, on the other hand, is formed from the accumulation of sediments and the melting of rocks.

What Is the Difference Between Oceanic Crust and Continental Crust?

Density

The difference in density has an impact on isostacy of crust floating on the semi-fluid upper mantle (asthenosphere), with continental crust (about 2.7g/cm³) rising or floating above oceanic crust (about 3.5 g/cm³).

Age

The continental crust is older than the oceanic crust. This fact can be easily explained by the recycling process of the oceanic crust. The recycling process does not happen to the continental layer. Consequently, this ensures that the oceanic layer is always younger geologically.

Location

Because continental crust is less dense than oceanic crust it floats higher on the mantle, just like a piece of Styrofoam floats higher on water than a piece of wood does.

Thickness

Oceanic crust is much thinner than continental crust. Oceanic crust is typically about 5-10 kilometers thick, while continental crust can be up to 40 kilometers thick.

Fossils

Oceanic crust is much younger than continental crust, so it does not contain as many fossils. Continental crust, on the other hand, is much older and contains a wealth of fossils. These fossils provide scientists with a valuable record of the evolution of life on Earth.

Mineralogy

Oceanic crust is rich in iron and magnesium, which are important for the formation of minerals such as magnetite and olivine. These minerals are important for the formation of rocks such as basalt and gabbro. Continental crust is rich in silicon and oxygen, which are important for the formation of minerals such as quartz and feldspar. These minerals are important for the formation of rocks such as granite and sandstone.