plate boundaries

Question 1

what is ridge push?

Answer 1

magma rises as the plates move apart (constructive plate margin)

Question 2

what is slab pull?

Answer 2

The denser plate sinks back into the mantle under the influence of gravity. this occurs at destructive plate boundaries

Question 3

what is a destructive plate margin?

Answer 3

the denser oceanic plate is subducted under the continental plate
subduction zone-deep oceanic trench
oceanic crust descends-friction and heat

volcanoes-composite (violent)
earthquakes-is where 90% if the earthquakes occur

example:Nazca and south american plate forming the andes

Question 4

what is a fault line?

Answer 4

it is a large scale landform found at constructive plate margin

Question 5

what happens to magma when it rises closer to the surface at a destructive plate margin?

Answer 5

it becomes more viscous and sticky producing composite volcanoes which are steep sided and have violent eruptions

Question 6

what is a constructive plate margin?

Answer 6

plates move apart
magma rises from the mantle to create new land
shield volcanoes
earthquakes

example:Iceland-mid Atlantic ridge (North American and Eurasian plates)

Question 7

what is a collision plate margin?

Answer 7

move towards each other
continental plates
neither can sink

landforms: fold mountains e.g. Himalayas
example:Australian and Eurasian plates

Question 8

what is a conservative plate margin?

Answer 8

plates slide past each other
no creation or destroyed land
moving in different directions or in the same direction but at different speeds
plate gets stuck-build up of pressure causing a jolt
sudden movement-earthquakes (violent)

Example:North American and Pacific plates (San Andreas fault)