Plate Movement

Question 1

theory on plate movement

Answer 1

• mantle convection

- slab pull and ridge push

Question 2

what is convection

Answer 2

hot rocks rising, cold rocks descending

Question 3

what is the asthenosphere

Answer 3

molten part of mantle (lower)

Question 4

what is the lithosphere

Answer 4

plates that are rigid, lying on lower mantle (asthenosphere)

Question 5

what is ridge push

Answer 5

magma rising as plates move apart which then cools in-between to form a new plate

Question 6

what is slab pull

Answer 6

a denser plate (oceanic) sinks into the mantle under a less dense plate (continental)

Question 7

what is the most active volcano in Europe

Answer 7

Mount Etna, Italy

Question 8

what causes convection currents

Answer 8

heat from the earth’s core is transferred to the mantle.

Question 9

what is a constructive (divergent) plate margin

Answer 9

-occurs when plates move apart (slab pull)

Question 10

what is an example of a constructive (divergent) plate margin

Answer 10

-Mid Atlantic Ridge (Iceland)

Question 11

how is pillow lava formed

Answer 11

at a constructive plate margin under the sea. Magma interacts with the water and turns into ‘pillow lava’

Question 12

what is palaeomagnetism?

Answer 12

palaeo - ancient

ancient magnetism

Question 13

where is palaeomagnetism found

Answer 13

under the ocean, in iron particularly - when the iron cools it alligns with the polarity of the earth (after underwater eruption)

Question 14

how are ‘magnetic stripes’ formed

Answer 14

underwater eruption, minerals w magnetic properties (iron) align with earth’s magnetic field as they cool.

-their particles lie in direction of magnetic pole

Question 15

how many reversals of magnetic polarity have there been over 40m years

Answer 15

171 reversals

Question 16

what land-forms are produced at constructive (divergent) plate margins

Answer 16

• rift valleysc (E Afr R Valley)
• volcanoes
• lakes

Question 17

3 types of destructive (convergent) plate margins

Answer 17

1. Oceanic- Continental (convergence)
2. Oceanic- Oceanic
3. Continental- Continental

Question 18

what happens at convergent (destructive) plate margin

Answer 18

thin oceanic crust (dense) forced beneath lighter continental crust

Question 19

what is subduction

Answer 19

plates move together - the denser oceanic crust slips down into the mantle and melts.

Question 20

what land-forms are produced at convergent (destructive) plate margins

Answer 20

• fold mountains (accumulated sediments)

- oceanic trench

Question 21

the zone where subduction takes place

Answer 21

Benioff Zone