Plate tectonics: Seafloor spreading/ magnetic striping

Question 1

How does the seafloor spread?

Answer 1

1. Two plates move away from each other at divergent plate boundaries
2. Magma from deep within the earth rises through the mid-ocean ridge
3. causing new oceanic crust to be formed

Question 2

What are the 3 plate boundaries associated with plate movements?

Answer 2

Divergent, convergent, transform

Question 3

What is the divergent plate boundary?

Answer 3

It is where 2 tectonic plates move apart

Question 4

What is the convergent plate boundary?

Answer 4

It is where 2 tectonic plates move towards each other

Question 5

What is the transform plate boundary?

Answer 5

It is where 2 tectonic plates slide past each other

Question 6

What are the types of plate boundaries for divergent plate boundary?

Answer 6

Oceanic-oceanic and continental-continental.

Question 7

What are the types of plate boundaries for convergent plate boundary?*

Answer 7

Oceanic-oceanic and continental-continental and oceanic-continental.

Question 8

What happens between oceanic-oceanic divergent plate boundaries?

Answer 8

1. Two oceanic plates move apart
2. There will be a decrease in overlying pressure, causing parts of the underlying mantle to melt, forming magma
3. The magma will rise though weak areas in the crust to the Earth’s surface, filling gaps caused by the spreading plates
   ( the magma/lava cools to form basaltic rocks)

Question 9

What happens between continental-continental divergent plate boundaries?

Answer 9

1. Two continental plates move apart
2. Rocks eventually fracture to form parallel faults
3. Rocks between these fault will fall to form a deep rift valley with steep sides
4. As the plates move apart, there is a decrease in underlying pressure, causing parts of the underlying mantle to melt, forming magma
5. Magma will rise through weak areas in the crust of the Earth’s surface, forming volcanoes

Question 10

What happens between oceanic-oceanic convergent plate boundaries?

Answer 10

1. Two oceanic plates collide
2. The denser plate will subduct beneath the other plate
3. Forming a deep depression known as the oceanic trench
4. The subducting plate will sink further into the mantle, causing high pressure to force water out of the oceanic crust. The water lowers the melting point of the overlying mantle, causing it to melt forming magma
5. The magma will rise through the weak areas to the Earth’s surface
6. Forming a chain of volcanoes, a volcanic island

Question 11

What happens between continental-continental convergent plate boundaries?

Answer 11

1. Two continental plates collide
2. Subduction does not take place as the plates are too buoyant
3. Enormous pressure causes the rocks to be uplifted and buckled to form fold mountains

Question 12

What happens between oceanic-continental convergent plate boundaries?

Answer 12

1. An oceanic plate collides with a continental plate
2. The denser oceanic plate will subduct beneath the continental plate
3. This forms an oceanic trench in the subduction zone
4. The subducting plate sinks into the mantle, where the high pressure forces water out of its oceanic crust. The water lowers the melting of the overlying mantle, forming magma
5. Magma rises through weak areas to the Earth’s surface, forming volcanoes on the continental plate
6. Enormous pressure at the plate boundary causes rocks on the continental plate to uplift and buckle, forming fold mountains