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)

"Floats" on top of the Mantle

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)

Underlies Ocean Basins

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