tectonic plates

Question 1

what is the crust?
(2 points)

Answer 1

the crust is the outer solid rock which is divided into 2 parts:
-Oceanic crust
-Continental crust

Question 2

what is the mantle?
(3 points)

Answer 2

the mantle is the thickest layer of the earth being roughly 2900km thick.
the upper rigid matle is in a viscuous, semi molten state.
The lower consists of molten magma which can easily flow.

Question 3

what is continental crust?
(2 points)

Answer 3

continental crust averages between 30-70km in thickness.
it is made up of light rocks such as granite.

Question 4

what is oceanic crust?

Answer 4

oceanic crust averages from 3-10km in thickness.
it is made up of heavy rock such as basalt.

Question 5

what is the asthenosphere?

Answer 5

this is what the lithosphere floats on and is the lower mantle

Question 6

what is the lithosphere?

Answer 6

it is the earths crust and rigid upper mantle

Question 7

define the inner core
(3 points)

Answer 7

it is solid due to the immense amount of pressure of overlying layers.
it is made of nickel and iron.
the hottest part in the inner core can reach up to 5000 degrees.

Question 8

define the outer core

Answer 8

the outer core is liquid state and is made up of iron

Question 9

who discovered the theory of continental drift?

Answer 9

Alfred Weneger in 1912

Question 10

who discovered the theory of sea-floor-spreading?

Answer 10

Harry hess 1960s

Question 11

name 3 supercontinents

Answer 11

1. Pangaea
   2.Gondwanaland
   3.Laurasia

Question 12

what are 4 pieces of evidence of continental drift?

Answer 12

1.Continental fit
2.Fossil distribution
3.common rock types
4.Matching glacial deposits

Question 13

how is continental fit proof of continental drift?

Answer 13

countries fit together like a jigsaw.
(America + Africa)

Question 14

how is Fossil Distribution proof of continental drift?

Answer 14

fossils which were found in south america were also found in africa

Question 15

how was common rock types proof of continental drift?

Answer 15

mountains in north america are part of ones found in ireland and scandanavia

Question 16

how is matching glacial deposits proof of continental drift?

Answer 16

ice sheets and glacial deposits in australia and africa were the same age and originated in the same place

Question 17

what does plate tectonics suggest?

Answer 17

continenets are transported across the planet due to convection currents which caused pangaea to break apart 200 million years ago.

Question 18

what does sea floor spreading suggest?

Answer 18

when plates split apart,magma rises from within the mantle.this creates new rock and a new ocean floor is formed

Question 19

what are 3 types of plate boundaries?

Answer 19

Divergent (constructive) boundary
Convergent (destructive) boundary
Transform (passive) boundary

Question 20

what 3 landforms are created from a divergent(constructive) plate boundary?

Answer 20

rift valleys
volcanic islands
mid ocean ridges

Question 21

what causes plates to seperate?

Answer 21

thermal convection currents which move in opposite directions, cause the plates to seperate and form a fissure.

Question 22

what does the fissure allow?

Answer 22

the fissure allows rising magma to rise above the surface and sollidify and create new land.

Question 23

what are 3 types of convergent(constructive) boundaries

Answer 23

Oceanic-Oceanic
Continental-continental
Oceanic-continental

Question 24

explain a transform (passive) boundary
(2 points)

Answer 24

rock is neither created nor destroyed.
plates slide past one another.