Layers of the Earth The Layers of the Earth are the Inner Core, Outer Core, Mantle and Crust.

Inner Core Iron and nickel SOLID and unattached to the mantle ~6000 degrees Celsius suspended in molten outer core depth of 5150-6370 kilometers (3219-3981 miles)

Outer Core iron and nickel molten (LIQUID) depth of 2890-5150 kilometers (1806-3219 miles) 37000 C convection motion within this region, along with the rotation of the Earth creates an effect that maintains the Earth's magnetic field

Mantle Facts iron (Fe), magnesium (Mg), aluminium (Al), silicon (Si) and oxygen (O) silicate compunds SOLID but can slowly deform in a plastic manner depth of 10-2890 kilometers(6-1806 miles) +10000 C convection in this region drives plate tectonics

Crust Facts Outermost layer of the Earth two types: oceanic and continental rocky and brittle fractures during earthquakes depth of 0-50 kilometers (0-31 miles) Primary elements are Silicon (Si) and Oxygen (O2)

Lithosphere The lithosphere is the outer solid part of the earth, part of the crust and uppermost mantle. The lithosphere is about 100 km thick. Rocks in the lithosphere are "rigid", meaning that they can bend but they cannot flow.

Asthenosphere Rocks in the asthenosphere are "plastic", meaning that they can flow in response to deformation. Even though it can flow, the asthenosphere is still made of solid (not liquid) rock; you can think of it kind of like Silly Putty.

Mantle Convection in the Asthenosphere Plastic rock (partially melted) is heated by the core, becomes less and rises. It cools at it nears the crust. When it cools, it becomes more dense and sinks. The process repeats creating CONVECTION CURRENTS.

Layers of the mantle Lithosphere: The thin outermost shell of the upper mantle is similar to the crust, though cooler and more rigid. Together with the crust, this layer is called the Earth’s lithosphere. Asthenosphere. The lithospheric plates “float” on a softer mantle layer called the asthenosphere. Their very slow motion is the cause of plate tectonics, a process associated with continental drift, earthquakes, volcanoes, and the formation of mountains. Upper mantle. Below the asthenosphere lies another layer, stronger and more solid than the asthenosphere. All layers below the crust down to a depth of about 670 kilometers (416 miles) are known as the upper mantle. Lower mantle. The rest of the mantle between the upper mantle and the core is known as the lower mantle. It is denser and hotter than the upper mantle.

Oceanic Crust Continental Crust Denser than continental crust Made primarily of basalt and gabbro 180 million years old or younger SOLID Composition of rocks are MAFIC (high in magnesium & iron) Rocks tend to be darker Note: Rocks between Mafic & Felsic are called Intermediate Less dense than oceanic crust Up to 4 billion years old Made of less dense rocks, such as granite SOLID Composition of rocks is mostly FELSIC (high in silicates) Rocks tend to be lighter

Temperature Increases There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.

Pressure Increases Density Increases The weight of all the rocks above squeezes those below Density Increases As pressure increases, the molecules are forced closer together. As molecules get more closely packed in a given area, the higher the density.