Section 8-2 Inside the Earth

The Composition of the Earth The Earth is divided into three layers- the crust, the mantle, and the core. The lightest materials make up the outer layers. The densest materials make up the inner layers.

The Crust The crust is the outermost and thinnest layer of the Earth. This is the layer that we live on. There are two types of crust- continental and oceanic.

The Mantle The mantle is the layer between the crust and core. It is very thick and contains most of the Earth’s mass. The composition is thought to have large amounts of iron and magnesium.

The Core Geologists think the core is made mostly of iron, with smaller amounts of nickel and possibly some sulfur and oxygen. It extends from the bottom of the mantle to the center of the Earth.

Layers of the Earth

The Structure of the Earth The Earth is divided into five main physical layers- the lithosphere, asthenosphere, mesosphere, outer core, and inner core.

Tectonic Plates Tectonic plates are pieces of the lithosphere that move around on top of the asthenosphere.

Major Tectonic Plates Pacific Plate North American Plate Cocos Plate Nazca Plate South American Plate African Plate Eurasian Plate Indian Plate Australian Plate Antarctic Plate

Tectonic Plates