What is the Difference Between Continental Crust and Oceanic Crust?

The main differences between continental crust and oceanic crust lie in their composition, density, age, and thickness. Here are the key differences:

• Composition: Oceanic crust is primarily composed of dark-colored rocks called basalt and gabbro, while continental crust is made of light-colored rocks called andesite and granite. Oceanic crust is dominated by mafic and ultramafic intrusive igneous rocks, whereas continental crust is dominated by granitic (felsic) intrusive igneous rocks.
• Density: Oceanic crust is denser, with a density of about 3.5 g/cm³, while continental crust has a lower density of about 2.7 g/cm³. This difference in density affects the isostasy of the crust, causing continental crust to "float" higher above the mantle than oceanic crust.
• Age: Continental crust is generally older than oceanic crust. Some parts of the continental crust are estimated to be about 4 billion years old, while oceanic crust is mostly young, continuously created at mid-oceanic ridges.
• Thickness: Oceanic crust is thinner, with a thickness of about 3 to 6 miles (5 to 10 kilometers), while continental crust is much thicker, reaching depths of up to 35 km on plains and 40 mi (70 km) on the highest mountains.

In summary, oceanic crust is young, dense, and composed of dark-colored rocks, while continental crust is older, less dense, and made of light-colored rocks. These differences in composition, density, age, and thickness result from the distinct formation processes and geological histories of the two types of crust.

Comparative Table: Continental Crust vs Oceanic Crust

Here is a table comparing the differences between continental crust and oceanic crust:

Continental crust is generally thicker, older, and more buoyant than oceanic crust. It is composed mainly of granite and felsic intrusive igneous rocks, while oceanic crust is dominated by mafic and ultramafic intrusive igneous rocks, such as basalt and gabbro. The continental crust has a density of around 2.6 g/cm³, while the oceanic crust has a higher density of 3.0 g/cm³.