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Earth’s Interior (What’s down there below us?)

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Presentation on theme: "Earth’s Interior (What’s down there below us?)"— Presentation transcript:

1 Earth’s Interior (What’s down there below us?)

2 There are 4 main layers inside Earth

3 How THICK are the layers?
(entire Earth is ~ 8000 miles wide) Crust: oceanic crust miles thick continental crust miles thick Mantle: about 1700 miles thick (2/3 of Earth’s mass) Outer core: about 1400 miles thick Inner core: about 1500 miles thick

4 How HOT are the layers? Crust: 0oC at surface  400oC where it contacts mantle Mantle: ~500oC to ~3700oC deeper down Outer core: ~4000oC Inner core: ~7000oC (hotter than the surface of the sun!!)

5 What are the layers made of?
Crust: Rock Mantle: Dense rock Outer core: Liquid metal (iron) !! Inner core: Solid metal (mostly iron)

6 Of course, it’s not quite that simple:
The “lithosphere” is the crust + part of the upper mantle. It is made of rock and is brittle. The “plates” of the earth’s crust make up the lithosphere. Below the lithosphere is a softer layer called the “asthenosphere”. In the asthenosphere, The rock is near it’s melting point, and flows very slowly, kind of like asphalt or tar.

7 Why the partly melted asthenosphere??
This graph shows why there is a layer of soft, partially melted rock (the ASTHENOSPHERE) in the top part of the mantle of the earth. From 100 to 200 km ( miles) below the surface, the temperatures are above the melting point of the rock - even at the very high pressure at this depth. MELTING POINT OF ROCK (yellow) ACTUAL TEMP (green) This layer - the ASTHENOSPHERE - is what the plates of the crust “float on” and explains why they can move around.

8 Finally – a very cool map showing thickness of earth’s crust (in km)
Continental crust is thick. Oceanic crust is thinner

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