Plate tectonics

Question 1

What is the most active on-land set of volcanoes present on earth

Answer 1

Pacific ring of fire

Question 2

Plate tectonics definition

Answer 2

describes how the Earth’s lithosphere moves around

Question 3

How many plates are there

Answer 3

7 major

6 minor

Question 4

Which is the biggest plate

Answer 4

Pacific

Question 5

example of a destructive plate boundary

Answer 5

Japan (continental) and Pacific (oceanic) - sea floor of Pacific plate is moving towards Japan at around 10 cm per year (Rothery, 2015) p.54

Question 6

How deep can EQ be tracked to

Answer 6

700km

Question 7

Example of a continent- continent collison

Answer 7

India colliding with Asia around 30 million years ago forming the Tibetan Plateau fringed to the south by the Himalayas

Question 8

Ophiolite

Answer 8

slice of oceanic lithosphere which has escaped subduction and has been preserved on land

Question 9

Divergent Plate Boundaries (constructive)

Answer 9

Where the two tectonic plates move apart allowing for new lithosphere to be formed

Question 10

Example- Oceanic divergent plate boundary

Answer 10

Mid ocean ridges (MORs) - formed of gabbro - similar to basalt but cools slower

Question 11

Example- Continental divergent plate boundary

Answer 11

Continental rift zones - e.g. East African Rift Zone

Question 12

Convergent (destructive) plate boundary

Answer 12

Where two plates move towards each other with the denser, older plate, usually the continental plate, is subducted beneath the newer, less dens plate

Question 13

Example- Oceanic- oceanic Convergent (destructive) plate boundary

Answer 13

Island Arcs- a chain of island which are parallel to a subduction zone
e.g. Allusion or Caribbean

Question 14

Example- Oceanic- continental Convergent (destructive) plate boundary

Answer 14

Active continental margins

e.g. Andean continental margin or Cascade margin (Canada and USA)

Question 15

Conservative Plate Boundary

Answer 15

where 2 plate slide past each other

Question 16

Example- oceanic Conservative Plate Boundary

Answer 16

transform faults

Question 17

Example- continental Conservative Plate Boundary

Answer 17

e.g. San Andres Fault

Question 18

How much is the San Andres Fault moving per year

Answer 18

the South west side of the fault (pacific) is moving north west at an average of around 1 cm per year relative to the rest of north america (Rothery, 2015) p.64

Question 19

Triple Junction

Answer 19

where 3 plates meet e.g. southern Chile - Nazca, South American and Antarctic Plates meet

Question 20

What combination of plates CANNOT occur at a triple junction

Answer 20

TTT = 3 trenches

Question 21

How many different combinations of plates can occur

Answer 21

16
R- ridge
T- trench
F- fault

Question 22

What is the most common combination of tripe junction plates

Answer 22

RRR

Question 23

Passive continental margins

Answer 23

not a plate boundary
e.g. edges of the Atlantic ocean
continental lithosphere is welded onto oceanic lithosphere with no relative motion between them - no treches, volcanoes and have a low seismicity