Which crust is thicker, older, and less dense than oceanic crust?

Which crust is thicker, older, and less dense than oceanic crust?

• A. Ocean
• B. Mantle
• C. Crust
• D. Continental

Answer: (D)

Continental crust is the thicker, older, and less dense type of crust compared with oceanic crust. It is mainly granitic in composition, giving it a lower average density (about 2.7 g/cm3) than the basaltic oceanic crust (around 3.0 g/cm3). Because of this lower density, continental crust can be much thicker—roughly 35 to 70 kilometers—while oceanic crust is much thinner, about 5 to 10 kilometers. Oceanic crust is continually formed at mid-ocean ridges and recycled back into the mantle at subduction zones, so its average age is relatively young. The mantle lies beneath the crust and is not crust itself. So the crust that is thicker, older, and less dense than oceanic crust is the continental crust.

Continental crust is the thicker, older, and less dense type of crust compared with oceanic crust. It is mainly granitic in composition, giving it a lower average density (about 2.7 g/cm3) than the basaltic oceanic crust (around 3.0 g/cm3). Because of this lower density, continental crust can be much thicker—roughly 35 to 70 kilometers—while oceanic crust is much thinner, about 5 to 10 kilometers. Oceanic crust is continually formed at mid-ocean ridges and recycled back into the mantle at subduction zones, so its average age is relatively young. The mantle lies beneath the crust and is not crust itself. So the crust that is thicker, older, and less dense than oceanic crust is the continental crust.