3.1.5.2 - Plate tectonics

Question 1

The 3 step process that occurs at destructive plate boundaries

Answer 1

1 - two plated are pushed together and the heavier oceanic plate sinks beneath the continental plate
2 - the plate sticks and locks as it tries to go under the continental plate
3 - heat from friction and the mantle cause the subducted plate to melt

Question 2

How do volcanoes and earthquakes from at destructive plate margins

Answer 2

Earthquakes - the friction between the two plates when it subducts
Volcanoes - when the plate melts it rises to the surface as plutons of magma and eventually turn into volcanoes

Question 3

What two landforms occur at destructive plate margins and how

Answer 3

Deep sea trenches - when the plate subducts beneath the other in the ocean water fills this space forming a trench e.g Nazca plate subducts beneath south-american causing the peru-chile trench

Island arcs - volcanoes formed from destructive plate margins that are located in the ocean - when they erupt this magma cools and forms land

Question 4

The 4 step process that occurs at constructive boundaries

Answer 4

1 - two plates move apart
2 - a gap arises ad magma fills this gap
3 - the rock solidifies to create new rocks on the sea bed
4 - over time the layers of the new rock build up above the surface level of the ocean

Question 5

What is formed here and how are 2 other landforms formed

Answer 5

• underwater volcanoes
• ocean ridges - when magma fills the gap and cools causing ocean ridge - volcanoes can occur along this
• rift valleys - plates move apart on land, brittle crust falls in to the gap forming horsts

Question 6

The 4 step process that occurs at conservative boundaries

Answer 6

1) two plates sliding in the same direction but the pacific plate is moving faster
2) when they slide past eachother they ‘snag’
3) Pressure and tension builds up as they lock together
4) Eventually they slide past eachother causing a sudden surge forward

Question 7

What occurs at the conservative boundary and what doesn’t

Answer 7

regular earthquakes

no volcanoes

Question 8

What other plate boundary does young fold mountains occur at and how

Answer 8

collision boundary
plates collide and there is not much subduction as it is two continental plates which are both light therefore edges and sediments are pushed upwards

Question 9

3 steps of how plates move and where are plates constructed and destroyed

Answer 9

• hot spots in the core cause magma to rise
• at the top it cools and sinks before arising again
• causes a convection current and causes the plates to move
• produced - constructive, destroyed - destructive