Earth layers

Earth layers

Earth’s LayersThe Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed.

This crust is not a solid shell; it is broken up into huge, thick plates that drift atop the soft, underlying mantle.

Thickness of the layers

The Core

• Below the mantle and to the center of the Earth

• Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium

Inner core

• Mostly solid iron• Hottest• Most pressure• Innermost layer

Outer core

• Above the inner core• Liquid molten metal

The Mantle

• Layer of Earth between the crust and the core

• Contains most of the Earth’s mass

• Has more magnesium and less aluminum and silicon than the crust

• Is denser than the crust

Mantle

• Largest layer• Solid, but flows slowly like putty• Contains the most mass• Upper mantle part of lithosphere• Lower upper mantle is part of asthenosphere

Crust

• Thinnest layer• Outermost layer• Coolest temp• Least pressure• 2 types- continental crust (land) thickest

–Oceanic crust (located under ocean) thinnest

Earth layersInfer from the graphs about the Earth below,

what happens as the depth increases?

• The deeper inside Earth, the higher the temperature and pressure.

• http://www.livescience.com/6959-hole-drilled-bottom-earth-crust-breakthrough-mantle-looms.html

Earth layers

• http://www.brainpop.com/science/earthsystem/earthsstructure/preview.weml

Tectonic Plates

Plate Tectonics

• Greek – “tektonikos” of a builder• Pieces of the lithosphere that move around• Each plate has a name• Fit together like jigsaw puzzles• Float on top of mantle similar to ice cubes

in a bowl of water

Continental Drift

http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml

Alfred Wegener 1900’sContinents were once a single land mass that drifted apart.

Fossils of the same plants and animals are found on different continents

Called this supercontinent Pangea, Greek for “all Earth”

245 Million years ago

Split again – Laurasia & Gondwana 180 million years ago

Evidence of Pangea

Lithosphere vs. asthenosphere

Lithosphere vs. asthenosphere

• What is the lithosphere?crust and uppermost mantlebroken into 30 plates

• What is the asthenosphere?plastic-like part of mantle under the lithosphereplates (lithosphere) move around on this

Lithosphere vs. asthenosphere

Lithosphere vs. asthenosphere

Plate tectonics

• BrainPOP “Plate tectonics”• http://

www.brainpop.com/science/earthsystem/platetectonics/