The Earth Contents

1. Structure

The Earth has a layered internal structure

The Earth has a rigid outer shell, or crust, sometimes known as the lithosphere. This is a thin veneer of soil, sand, gravel and bedrock, which is in contact with the atmosphere and the hydrosphere. The importance of the crust lies in its accessibility and its resource base rather than its size. The solid layers of the mantle lie underneath the lithosphere. The mantle is divided into an inner region, which is believed to consist of oxides of magnesium and silicon, and an outer region of iron and magnesium silicates. There are connections between the crust and the mantle which add (or remove) relatively small amounts of material (volcanic activity is one such connection). It is, in general, reasonable to consider the crust as isolated from the mantle, i.e. as a closed system. The core lies underneath the mantle, with at least some of the core being a liquid.

The Earth's layers

What are the main layers of the Earth's internal structure?