Divergent plate boundaries

Question 1

Paleomagnetism

Answer 1

Earths magnetic field is not constant, the poles switch every couple hundred thousand years
We know this through the magma that comes out of rift zones: The magma is Fe rich and when it comes out and crzstallizes, you notice that they are aligned in a certian direction– the direciton corresponding to the magnetic field of the Earth
A barcode like structure/pattern visible

Question 2

4 stages of divergent plate formation

Answer 2

1. Plume formation
2. East Atlantic Rift valley
3. Red Sea
4. Mid Atlantic Ridge

Question 3

Mantle plume

Answer 3

1.Narrow section of mantle is hotter = less dense –> rises
2.

Question 4

How Plume –> Rift zone?

Question 5

Rift valley is made up of

Answer 5

horst and graben structure, normal faulting
strike-slip faults too at mature margins

Question 6

Earthquakes

Answer 6

Minor earthquakes, caused by strike slip action/fault

Question 7

Volcanism

Answer 7

Passive and mostly in the deep ocean environment
Except iceland