Plate Tectonics

Question 1

What are plate tectonics?

Answer 1

Plate tectonics refer to the study of the movement of the tectonics plates over millions of years. The continental drift theory and sea floor spreading are the major theories supporting plate tectonics.

Question 2

What are tectonic plates?

Answer 2

Tectonic plates are huge slabs of lithosphere floating on the mantle (asthenosphere).

Question 3

What are plate margins? Name the three types.

Answer 3

Plate margins are the boundaries where 2 tectonic plates meet. There are three types; constructive/divergent, destructive/convergent and transform/conservative.

Question 4

Describe what happens at convergent/destructive plate margins.

Answer 4

1. There are two types - subduction and upliftment

Subduction -
1. When oceanic and continental crusts collide
2. As the oceanic crust is denser, it goes underneath the continental crust
3. This results in the formation of volcanoes and oceanic trenches (depressions in the sea floor)

Upliftment -
1. When 2 continental crusts collide
2. Results in the formation of fold mountains and earthquakes
3. Fold mountains are created because the materials on top rise to make these structures

Note -
1. It is very rare for 2 oceanic plates to converge
2. Results in the formation of volcanoes and oceanic trenches
3. Subduction will occur but not like how it occurs with oceanic plates and continental crusts

Question 5

Describe what happens at divergent/constructive plate margins.

Answer 5

1. Earthquakes do not occur
2. They have shield volcanoes (volcanoes which aren’t mainly destructive and just create new crust - for examples in Iceland)

Question 6

Describe what happens at transform/conservative plate margins.

Answer 6

1. Movement is mainly horizontal
2. Always result in Earthquakes
3. Example - the San Andreas fault

Question 7

Name some major plates.

Answer 7

The Antarctic plate, the North American plate, the South American plate, the Pacific plate, the India-Australia-New Zealand plate (Australian plate and the Indian plate), The Africa with the eastern Atlantic floor plate (The African plate), the Eurasia and the adjacent oceanic plate (The Eurasian plate).

Question 8

Name some minor plates.

Answer 8

The Cocos plate, the Nazca plate, the Arabian Plate, The Philippine plate, the Caroline plate, the Fuji plate and the Juan De Fuca plate.