Summary
Key Things we’ve looked at!
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The various layers of the Earth including where they are, what they are made of and how they behave physically.
Let’s be specific! Good to know the following!
a. The CRUST is the low density outer portion of the lithosphere. Crust can be continental or oceanic.
b. The lithosphere is the outer brittle portion of the earth– and it includes the upper mantle and crust.
c. The asthenosphere is still really the outer part of the mantle, but it’s below the lithosphere, and is closer to its melting point (but not wholly molten). It might have some small pockets of melting, but it is a solid, albeit a “mushy-gushy” solid, kind of like hot tar, or toothpaste!
d. The deep mantle is very much a solid.
e. The outer core is liquid metal (iron-rich).
f. The inner core is solid metal (iron-rich). -
We’ve seen how geologists use indirect methods to study earth’s interior (e.g. magnetism, gravity, seismic waves).
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Earth’s magnetic field is generated in the outer liquid core, and it episodically reverses itself over time (on scales of a few hundred thousand to a million years)
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Earth’s interior, and in particular its heat transfer and influence on rock physical properties (rigid versus dutile) generates plate tectonics
Examples
Did you enjoy the video through the layers of the Earth we watched at the beginning of this outcome? It was a very short trip but very informative. Now you know why geologists sometimes have issues with Hollywood and the movies that we see sometimes. Journey to the Center of the Earth may be a fun movie (acting aside), but it is totally unrealistic. As you saw, the temperatures and pressures inside the Earth make it impossible for us to actually visit there, although I know a lot of geologists would love to make the trip!