Lecture 3 16/01/2017

Question 1

Radius of earth

Answer 1

6371 km

Question 2

Continental crust v. oceanic crust .

Answer 2

Continental
1) Granitic

2) Thickness = 35 - 40 km, 60 -70 km under mountains
3) Age is > 1.5 BY

Oceanic
1) Basaltic

2) Thickness = 6km
3) Age is < 200 MY

Question 3

How long ago was Pangea?

Answer 3

225 MYA

Question 4

What is “Polar Wandering”?

Answer 4

The slow and erratic, real or apparent, movement of the earth’s rotational or magnetic poles relative to the continents throughout geological time, due largely to continental drift.

Question 5

What type of plate boundary is the Mid-Atlantic Ridge an example of?

Answer 5

Divergent plate boundary (i.e., sea floor spreading)

Question 6

What are the 3 types of plate boundaries?

Answer 6

1. Convergent plate boundary - one plate is subducted beneath another (subduction);
2. Divergent plate boundary - plates move apart (i.e., sea floor spreading); and
3. Transform fault - shearing (e.g., San Andreas Fault, Cali).

Question 7

On average, how far do the continents move every year?

Answer 7

2 - 3 cm

Question 8

What type of rock would you expect to find on the sea floor?

Answer 8

Basaltic rock (Igneous).

Question 9

Surface subsistence

Answer 9

the land surface above an aquifer experiences a decrease in elevation.