Inside the Earth Composition What it is made

Inside the Earth

Composition (What it is made of) • Crust • Mantle • Core

The Crust • Outer layer • 5 -100 km thick • 2 types of crust – Oceanic (very dense, made of basalt) – Continental (less dense, made of granite)

Oceanic and Continental Crust

Layers of Earth Crust • Basalt: Ocean crust made of dark dense rock and is very thin • Granite: Continental crust that is less dense but is thicker (especially where mountains are present) Continental Crust Oceanic Crust 2 -3 miles thick Basalt More dense 20 -35 miles thick Granite Less dense

The Mantle • Middle layer • Very thick layer • 3, 000 km thick

Layers of Earth Mantle • Lithosphere: upper most part of the mantle and lower part of the crust • About 100 kilometers thick • Solid and broken up into plates by cracks Lithosphere

Layers of Earth Mantle • The temperature and pressure in the mantle increases with depth • The increasing pressure and high temperature cause the lower part of the mantle (asthenosphere) to be soft and gives it the ability to flow easily (plasticity)

Layers of Earth Mantle • Asthenosphere: Lower, plasticity part of the mantle that flows easily • The core heats this section of the earth, and causes convection current to flow here Asthenosphere

The Core • Made mostly of iron • 1/3 of the earth’s mass • Very hot

Earth’s Layers • How are the earth’s layers similar to an egg? • Shell=crust • Egg white=mantle • Yolk=core

Layers of Earth Core • Outer core: thick liquid, molten material • Inner core: dense ball of solid metal (iron and nickel)

Physical Structure of the Earth (5 Layers) • Lithosphere- rigid outer layer (crust) • Asthenosphere- solid rock that flows slowly (like hot asphalt) • Mesosphere- middle layer • Outer Core- liquid layer • Inner Core- solid, very dense

Tectonic Plates • Earth’s crust is broken into about 19 pieces • These plates move on top of the asthenosphere