Which crust is thinner, younger, and denser than continental crust?

Which crust is thinner, younger, and denser than continental crust?

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

Answer: (B)

Oceanic crust fits those properties. It’s thinner than continental crust because it’s built as basaltic rock at mid-ocean ridges and doesn’t accumulate the thick, buoyant granitic material that forms continents. It’s younger on average because new ocean floor is constantly created at ridges and older ocean crust is recycled back into the mantle at subduction zones, so most of it is geologically recent. It’s denser due to its basaltic composition, which is rich in iron and magnesium, making it heavier per volume than the granitic rocks that compose continental crust. By contrast, continental crust is thicker, less dense, and much older, while the mantle and core are not crust at all.

Oceanic crust fits those properties. It’s thinner than continental crust because it’s built as basaltic rock at mid-ocean ridges and doesn’t accumulate the thick, buoyant granitic material that forms continents. It’s younger on average because new ocean floor is constantly created at ridges and older ocean crust is recycled back into the mantle at subduction zones, so most of it is geologically recent. It’s denser due to its basaltic composition, which is rich in iron and magnesium, making it heavier per volume than the granitic rocks that compose continental crust. By contrast, continental crust is thicker, less dense, and much older, while the mantle and core are not crust at all.