1. Composition:
- Crust: Primarily composed of lighter elements like silicon, oxygen, aluminum, and iron. It's further divided into oceanic crust (thinner, denser, primarily basalt) and continental crust (thicker, less dense, primarily granite).
- Mantle: Composed mainly of silicate minerals like olivine and pyroxene. It has a higher density than the crust due to the presence of heavier elements like magnesium and iron.
2. Physical State:
- Crust: Solid and rigid. It's the outermost layer and is divided into tectonic plates that move and interact.
- Mantle: Behaves like a very viscous fluid over long periods, allowing for the movement of tectonic plates. It's mostly solid but has a partially molten layer called the asthenosphere.
3. Thickness:
- Crust: Relatively thin, ranging from 5-70 km (3-43 miles) in thickness. Oceanic crust is thinner than continental crust.
- Mantle: Much thicker than the crust, extending about 2,900 km (1,800 miles) deep.
In short: The crust is the thin, solid, and less dense outer layer of the Earth composed of lighter elements, while the mantle is the thick, viscous, and denser layer beneath it, composed of heavier elements.
