1.2 seafloor spreading

Question 1

seafloor spreading

Answer 1

a process where magma from deep within the earth rises through mid ocean ridges to create new oceanic crust at divergent plate boundaries

Question 2

landforms

Answer 2

formation on land due to plate movement

Question 3

mid ocean ridge

Answer 3

a submarine mountain chain linearly located on the ocean floor at divergent plate boundaries

Question 4

oceanic trench

Answer 4

deep depression found in the ocean floor where one oceanic plate is subducting beneath another plate

Question 5

evidence of seafloor spreading

Answer 5

1. where 2 oceanic plates move away from each other at divergent plate boundaries, seafloor spreading occurs
2. magma from deep within the earth rises through the mid oceanic ridge
3. new oceanic crust is formed
4. overtime a mid oceanic ridge is formed. this is why divergent boundaries are also known as constructive boundaries.

Question 6

1. evidence of seafloor spreading

Answer 6

when two oceanic plates move away from each other at divergent plate boundaries, seafloor spreading occurs

Question 7

2. evidence of seafloor spreading

Answer 7

2. magma from deep within the earth rises through the mid oceanic ridge

Question 8

3. evidence of seafloor spreading

Answer 8

new oceanic crust is formed

Question 9

4. evidence of seafloor spreading

Answer 9

overtime, a mid oceanic ridge is formed. this is why divergent boundaries are also known as constructive boundaries

Question 10

description of age of rocks

Answer 10

• the age and distance of crust from the mid oceanic ridge has a direct relationship
• crust increase in age with increasing distance from the oceanic ridges and vice versa

Question 11

explanation of age of rocks

Answer 11

1. pattern supports the concept of seafloor spreading, where new crust is continuously created at the zone of divergent plate boundaries where oceanic ridges can be found
2. as divergence continues, older crusts are pushed laterally outwards on both sides of the ocean ridge
3. hence, the pattern shows that this is not a random or isolated occurrence and proving that plates move away

Question 12

1. explanation of age of rocks

Answer 12

the pattern supports the concept of seafloor spreading, where new crust is continuously created at the zone of divergent plate boundaries where oceanic ridges can be found

Question 13

2. explanation of age of rocks

Answer 13

as divergence continues, older crusts are pushed laterally outwards on both sides of the ocean ridges

Question 14

3. explanation of age of rocks

Answer 14

hence, the pattern shows that this is not a random or isolated occurrence and proving that plates move

Question 15

description of limited sediment accumulation

Answer 15

as plates continue to move away from, the divergent boundary, little sediment accumulation is found at the convergent boundary at the oceanic trenches

Question 16

explanation of limited sediment accumulation

Answer 16

1. proving that new crust is continually formed at divergent boundaries at mid oceanic ridges and mover laterally, where older crust is destroyed at oceanic trenches
2. hence oceanic crusts are usually younger than continental crust

Question 17

1. explanation of limited sediment accumulation

Answer 17

proving that new crust is continually formed at divergent boundaries at mid oceanic ridges and mover laterally, where older crust is destroyed at oceanic trenches

Question 18

2. explanation of limited sediment accumulation

Answer 18

hence oceanic crusts are usually younger than continental crusts