EQ1: 1.2

Question 1

What is the pangaea map?

Answer 1

World map of all the continents together 200 million years ago

Question 2

What did Ortelius discover?

Answer 2

South America & Africa were similar shape - believed they were once connected but continental drift happened

Question 3

How did Alfred Wegener adapt this theory?

Answer 3

Gave more evidence by finding fossils from Africa which were found in South America (Found this in many other continents) - therefore all continents were once together

Question 4

How did Arthur Holmes explain how the continental drift occured?

Answer 4

Thermal convection (convection currents) in the mantle

Question 5

Name the theories of plate tectonics

Answer 5

Internal Structure
Slab Pull
Mantle Convection
Seafloor Spreading
Subduction
Palaeomagnetism

Question 6

Explain the Internal Structure

Answer 6

Lithosphere broken into tectonic plates on the asthenosphere

Question 7

Definition of Lithosphere

Answer 7

Crust and upper part of the mantle

Question 8

Features of Asthenosphere

Answer 8

• Pressure & heat increased

- Molten rock (not liquid or solid)

Question 9

Explain Slab Pull

Answer 9

Newly formed ridge - gets denser and thicker as it cools - therefore sinks in mantle under its own weight pulling the rest of the plate down - divergent plate boundary

Question 10

Explain Mantle Convection

Answer 10

Heat radiating in inner core - convection created at mantle - convection currents make contact and move plates by frictional drag

Question 11

Explain Seafloor Spreading

Answer 11

Hot magma forced up asthenosphere & hardens - pushing tectonic plates apart - divergent plate boundary

Question 12

Explain Subduction

Answer 12

Oceanic plate slides under continental plate - subduction zone - convergent plate boundary

Question 13

Explain Palaeomagnetism

Answer 13

Evidence of seafloor spreading - examination of the polarity of rocks - make up ocean floor - Pattern mirrored on either side of mid-oceanic ridge - oceanic crust slowly spreading away from boundary - magnetic field

Question 14

Describe the Benioff zone

Answer 14

Important to determine magnitude - determines depth and position of point of rupture - strain energy from plates is stored - released along fault

Question 15

What are Hypocentres?

Answer 15

Point where energy is released

Question 16

Why is it that shallow Hypocentres tend to be more destructive?

Answer 16

As the distance is less for the seismic waves to travel