What is the difference between oceanic and continental crust?


Quick Answer

Continental crust is part of the Earth’s surface found under land masses, and oceanic crust is the surface found under the ocean floor. Oceanic crust is made of dense rock like basalt. Continental crust has rocks of lesser density like granite.

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Full Answer

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 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 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.

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