Sci 7: Earth's Layers

Core

Earth's innermost layer- made mostly of the metals iron and nickel (about 3,486 km thick)

Inner Core

A dense sphere of solid iron and nickel at the center of Earth (solid due to intense pressure)

Outer Core

A layer of molten iron and nickel that surrounds the inner core of Earth

Crust

Earth's outermost and thinnest layer- made up of solid rock that includes both dry land and the ocean floor.

Asthenosphere

a subdivision of the mantle situated below the lithosphere composed of hot, semi-solid material (similar to hot tar)

Mantle

the layer of the earth between the crust and the core- about 3,000 km thick, made up of rock that is very hot, but solid

Oceanic Crust

the portion of Earth's crust that includes all the ocean floor and not associated with continental areas, thinner and higher in density than continental crust, consists mostly of basalt

Continental Crust

the portion of the earth's crust that includes all continents and some major islands, is less dense than oceanic crust, and is 20-50 km thick, consists of mostly of granite

Lithosphere

the rigid outer layer of Earth, including the crust and uppermost rigid part of the mantle (100 km thick)