Plate Tectonics Flashcards
1
Q
What is continental drift
A
- the continents have changed with time
- alfred wegener 1912
- pangea split into gondwanaland and laurasia
2
Q
How was sea floor spreading proposed?
A
- harry hess 1960s
- basaltic magma from the mantle rises creating new ocean floor at mid ocean ridges
3
Q
Lithosphere features
A
- crust and upper mantle
- rigid and brittle
- carried by moving the underlying asthenosphere
4
Q
Oceanic and continental plate differences
A
Oceanic:
- 5km thick
- 2.9gcm-3 density
- 200Ma oldest rock
Continental:
-300km thick
-2.7gcm-3
- 3960Ma oldest rock
5
Q
A
