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Sima, Oceanic Crust

Sima – Oceanic Crust

The ocean floor is made primarily of extremely dense rock which scientists call sima. Sima is made out of two basic substances. These substance are silica, and magnesium.

Sima - The Ocean Floor

Sima tends to be younger than the rocks found on continents. Scientists believe that a layer of sima also underlies the continents, so that it is below them.