Features Of Plate Margins

Question 1

What features occur at constructive plate margins? (Features tectonics)

Answer 1

• mid-oceanic ridge
• volcanoes
• Rift Valley

Question 2

What does sea floor spreading cause at constructive plate margins? (Features tectonics)

Answer 2

1) mid-oceanic ridge = an underwater mountain range

2) volcanoes = magma rises between the diverging plates

Question 3

What does continental rifting cause at constructive plate margins? (Features tectonics)

Answer 3

1) rift valleys = parts of the crust form parallel faults

2) volcanoes = magma rises between the diverging plates

Question 4

What does features form at conservative plate margins? (Features tectonics)

Answer 4

Crustal faulting = plates slide past each other, pressure builds to stress, eventually released into an earthquake

Question 5

What features form at continental-continental destructive plate margins? (Features tectonics)

Answer 5

Fold mountains = when two continental plates meet, sediment accumulates through the force one has on the other, moving upwards

Question 6

What features form at oceanic-continental destructive plate margins? (Features tectonics)

Answer 6

1) deep ocean trenches = oceanic plate is denser so subducts and is pulled down forming a trench
2) volcanoes = the deeper a plate is pushed, the hotter the surroundings. Heat generated by friction causes the plate to melt in the Benioff zone. Molten material is less dense so rises

Question 7

What features form at oceanic-oceanic destructive plate margins? (Features tectonics)

Answer 7

1) deep ocean trenches = oceanic plates build up tension, eventually one gives in and subducts
2) island arcs = magma rises to the surface of the ocean floor forming a line of volcanoes

Question 8

What are hotspots formed by? (Features tectonics)

Answer 8

An area or concentrated radioactive decay in the core heats above (lower mantle) creating strong localised thermal currents, causing a magma plume

Question 9

What happens when the magma plume from a hotspot reaches the crust? (Features tectonics)

Answer 9

Crust melts, forming active volcanoes - eventually convection currents move these away and more form

Question 10

Where do hotspots occur and what is an example? (Features tectonics)

Answer 10

• In the middle of plates, far away from the boarder

* Hawaii - middle of the Pacific plate

Question 11

Where do earthquakes occur and why? (Features tectonics)

Answer 11

At any boundary because the plates are moving