Help 10 points!! Compare and contrast the two types of crust.?

Question

Help 10 points!! Compare and contrast the two types of crust.?

Answer 1

There are two different types of crust: thin oceanic crust that underlies the ocean basins and thicker continental crust that underlies the continents. These two different types of crust are made up of different types of rock. The thin oceanic crust is composed of primarily of basalt and the thicker continental crust is composed primarily of granite. The low density of the thick continental crust allows it to "float" in high relief on the much higher density mantle below.

Answer 2

CONTINENTAL CRUST VERSUS OCEANIC CRUST

CONTINENTAL CRUST

Less Dense (lighter weight): average density = 2.7 gm per cubic centimeter

Thicker: 0 to 40 km, average 35 km under high mountains, the crust can be thickened, up to 65 km. Under the craton, the average thickness is 30 km.

Mineral Composition: granitic (felsic) rocks such as granodiorite and granite enriched in Potassium (K), Sodium (Na), Aluminum (Al), and Silica (Si)

Typically darker color in appearance.

"Floats" on top of the Mantle due to being less dense, (it is buoyant).



The continental crust is older than oceanic crust.

OCEANIC CRUST

More Dense (heavier): average density = 3.0 gm per cubic centimeter

Thinner: 0 to 10 km, average 5 km, thinnest at Mid-Ocean Ridges

Mineral Composition: mafic rocks such as basalt and gabbro enriched in Magnesium (Mg) and Iron (Fe)

Typically lighter in color when compared to oceanic crust.

Underlies Ocean Basins

Oceanic crust is younger than continental crust (200 million years old or less) due to continuous recycling at subduction zones.