GEOLOGY

Detailed explanation-1: -It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however, it is denser, having a mean density of about 3.0 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter.

Detailed explanation-2: -Oceanic crust is generally composed of dark-colored rocks called basalt and gabbro. It is thinner and denser than continental crust, which is made of light-colored rocks called andesite and granite. The low density of continental crust causes it to “float” high atop the viscous mantle, forming dry land.

Detailed explanation-3: -As stated, oceanic plates are denser than continental ones. This is because they are made of denser rocks. Oceanic plates are typically composed of basalt. Basalts are mafic igneous rocks, which means they have a silica (quartz) content of less than 20% and are created by the cooling of lava.

Detailed explanation-4: -Oceanic crust is thinner, but denser than continental crust. Continental crust is thicker, but less dense. So when the two collide, the heavier, oceanic crust subducts below the continental crust.

Detailed explanation-5: -Continental crust is less dense than oceanic crust (2.7 g/cm3 vs. 3 g/cm3), and it is much older.