Earth Dynamics

Question 1

Alfred Wegener proposed that _______ moved about the face of the planet.

Answer 1

Continents

Question 2

Describe the characteristics of Earth’s major tectonic plates.

Answer 2

Constitutes the lithosphere. Behaves as strong rigid layer. Overlies weaker region in mantle (asthenosphere) and moves due to convection in the mantle. All major interactions occur along these boundaries.

Question 3

The breaking of the supercontinent Pangea occured in the _____ period.

Answer 3

Cretaceous, the age of the dinos! (So, really, should have been ‘Cretaceous’ park.)

Question 4

What are five pieces of evidence for the Continental Drift?

Answer 4

1. Continents fit like puzzle pieces (ex. South America and Africa)
2. Evidence of ancient ice ages match all over the globe. (ex. the South Pole in Gandwana, one of the supercontinents).
3. Fossil evidence across the Atlantic Ocean (South America and Africa again). The mesosaurus.
4. Paleomagnetics at the bottom of the ocean (the Earth periodically switches magnetic poles, and the igneous rocks at the bottom of the ocean will reverse polarity, forming a pattern).
5. Structural similarities in geo structures from regions across the oceans (Cape Breton in Canada vs. formations on the Scottish Coast).

Question 5

How did the Hawaiian islands form?

Answer 5

Crust moving over a stationary hot spot. The volcanos are stationed in a way such that you can see how the crust moves over the hot spot. Islands that are farther away are older. If one can date the islands, we can note their speed!

Question 6

What are the main plate boundary types?

Answer 6

Diverging (plates separating). Mainly at mid-ocean ridges.

Transforming (plates shifting against each other). Often forms faults (as if someone took a knife and split the land).

Converging (plates overlapping). Subduction zones = consumption of crust into mantle.

Question 7

What is ‘isostasy’?

Answer 7

Explains why the Earth is not smooth. Envision thick and thin blocks floating on a body of water: the thin blocks float lower (less of them are exposed on the surface) and the thicker blocks float higher (more are exposed on the surface).

Question 8

Why is Japan prone to earthquakes and tsunamis?

Answer 8

There is a very large subduction zone along the border of Japan. This can account for the massive tsunamis and earthquakes Japan is often subject to.