Tectonics and volcano formation

Question 0

What happens at a divergent plate boundary?

Answer 0

2 oceanic plates are present
magma rises and forces the edge of the plates upwards, forming a mid atlantic ridge
cracks and fissures release magma that rises, cools and solidifies forming volcanoes

Question 1

What two kind of plates are present at a divergent plate boundary?

Answer 1

2 oceanic plates

Question 2

What are the characteristics of an oceanic plate?

Answer 2

Thin - 7km
Young
Basalt

Question 3

What are the characteristics of continental plates?

Answer 3

thick - up to 70km
older
granite

Question 4

What are the two types of plates?

Answer 4

Oceanic and continental

Question 5

True or false: ‘The asthenosphere moves the lithosphere’

Answer 5

True

Convection currents in the asthenosphere moves the lithosphere. (Hottest magma rises and cools and sinks)

Question 6

Name the three types of plate boundaries

Answer 6

• Divergent
• Convergent
• Conservative

Question 7

True or false: ‘at a divergent plate boundary the plates are moving away from each other’

Answer 7

true

Question 8

At a convergent plate boundary the two plates are moving:

a) towards each other
b) away from each other
c) sliding past each other

Answer 8

a) at a convergent plate boundary the plates are moving towards each other under compression

Question 9

with 2 oceanic plates present at a convergent plate boundary, what would be formed?

Answer 9

Island arcs - volcanoes in the sea

Question 10

two continental plates at a convergent plate boundary form…..

Answer 10

extremely high mountains e.g Himalayas

continent collision

Question 11

What is continent collision?

Answer 11

2 continental plates at a convergent plate boundary

Forms extremely high mountains

Question 12

What plates would be found to form smaller mountains such as the Andes

Answer 12

An oceanic subducting beneath a continental

Question 13

What is a strike-strip fault?

Answer 13

2 plates sliding past each other in opposite directions (conservative plate boundary)

Question 14

What happens to the end of a subducted plate?

Answer 14

It melts in the asthenosphere creating magma, this magma rises and creates a magma chamber

Question 15

What is it called where two plates touch?

Answer 15

The Benioff zone

Question 16

Which plate subducts beneath the other?

Answer 16

The oceanic crust subducts beneath the continental
OR if faced with two oceanic crusts at a convergent plate boundary
The older, cooler denser oceanic crust

Question 17

What magma type is at the divergent plate boundary?

Answer 17

Basaltic

Question 18

What is the silica content at a divergent plate boundary?

Answer 18

45-54% low

Question 19

Is the magma runny or viscous at a divergent plate boundary?

Answer 19

Runny

Question 20

T/F

The plate boundary that lets out gas most easily has explosive eruptions

Answer 20

False
With easy gas escape, the lower the explosivity
When gas builds up it becomes explosive

Question 21

T/F

Rhyolitic magma type at a continental vs oceanic convergent plat boundary is rich in silica

Answer 21

True

>70% silica content

Question 22

What is the magma type found at a hotspot?

Answer 22

Basaltic

Question 23

What is the magma type found at a convergent oceanic oceanic plat boundary?

Answer 23

Andesitic