Hazards:Theory of plate tectonics

Question 1

core characteristics

Answer 1

dense rock
5000°C+
iron and nickel
inner core is solid
outer core is molten

Question 2

mantle characteristics

Answer 2

motlen/ semi-molten
silicon and oxygen

Question 3

crust characteristics

Answer 3

solid
varies in thickness
oxygen,aluminium,etc

Question 4

what is the earths crust divided into

Answer 4

lithosphere and asthenosphere

Question 5

Alfred Wegners theory

Answer 5

pangea and proposed the theory of continental drift

Question 6

evidence that supported Alfred Wegner

Answer 6

-East coast of South America and West africa fit
-matching rock sequences in Canada and Scotland
-fossils from similar species found in India and Australia

Question 7

why was Alfred’s theory rejected ?

Answer 7

he didn’t explain how the plates moved

Question 8

what is convection?

Answer 8

the circulation of material caused by differences in density

Question 9

what explains the movement of plates

Answer 9

sea floor spreading-

Question 10

what happens in ridge push

Answer 10

@ constructive margins magma rises ,forms new crust. Very hot expands above the surface forming a slope which puts pressure on plates causing them to move apart.Gravity pushes the plates further away, widening the gap (Gravitational sliding)

Question 11

what happens in slab pull?

Answer 11

@ destructive margin as a plate or dense plate subducts gravity pulls on the rest of the plate with a force called slab pull

Question 12

landforms at a constructive plate boundary

Answer 12

-ocean ridges
-rift valley

Question 13

landforms at a destructive plate boundary

Answer 13

-young fold mountains
-deep sea trenches
-island arcs

Question 14

ocean ridges example and explanation

Answer 14

e.g. mid altlantic
—^— -magma rises up and forms submarine volcanoes

Question 15

rift valley example and explanation

Answer 15

e.g. East african rift valley
-two continental plates move apart and land in the middle sinks and leaves a gap

Question 16

what is a horst

Answer 16

land between two rift valleys

Question 17

deep sea trenches example and explanation

Answer 17

e.g.Mariana trench
oceanic plate subducts underneath continental and melts

Question 18

island arcs example and explanation

Answer 18

as oceanic plate melts it rises up in magma plumes and forms new land

Question 19

young fold mountains example and explanation

Answer 19

e.g. Himalayas> mt Evrest
continental and continental crust move toward each other and pushed upwards