Features Of Oceans

Question 1

How are mid ocean ridges formed

Answer 1

Convection currents caused by radioactive decay in the core heats the bottom of the mantle becoming less dense it rises and cools and creates a convection current the friction pulls the plates apart magma rises and cools and forms rocks

Question 2

What is the continental shelf

Answer 2

Flat plains located beneath the drowned edge of continents slope angle of 0.5 degrees

Question 3

Continental rise

Answer 3

Below shelf break average angle of 4 degrees

Question 4

sub marine canyon

Answer 4

found on the continental slope these features are steep sided with v shaped profiles and topographic releif up to 2 km

Question 5

abyssal plain

Answer 5

flattest areas on earth having regional slopes of 0.5 degrees lie at water depths of 3-5 km

Question 6

abyssal hill

Answer 6

domes or elongated hills that are no higher than 1000 metres high

Question 7

seamount

Answer 7

any type of abyssal mountain that rises above 1000 metres that does not extend out off the waters surface

Question 8

guyot

Answer 8

flat topped sea mounts their tops were once active volcanoes bit there tops were levelled by erosion edges colonised by coral reefs

Question 9

trench

Answer 9

steep sided long and narrow depressions some 3-5km deeper than the ocean floor

Question 10

continental slopes

Answer 10

nearly flat plains that are located between continents average 6 km in width slopes gently sea ward

Question 11

what 3 things affect salinity

Answer 11

freezing/evaporation of water
lots of rain
rivers and streams

Question 12

what overall factors affect ocean currents

Answer 12

coasts
Coriolis affect
planetary winds
variation in temperature

Question 13

how does wind affect ocean water

Answer 13

wind creates friction that creates waves
pulls water along

Question 14

what is the Coriolis effect

Answer 14

earth spins quicker at the centre so water is deflected towards the poles clockwise for the N. hemisphere and anticlockwise for the S. hemisphere

Question 15

what are gyres

Answer 15

large areas of circulating water in the sea caused by Coriolis effect

Question 16

why are some currents warm

Answer 16

found in warm areas possibly near the equator
i.e. gulf stream

Question 17

how does freezing/evaporation of water effect water salinity

Answer 17

evaporation - when water evaporates the water leaves but the salt doesn’t so all that is left is the salt increasing salinity freezing- when water freezes water is taken out of the ocean as ice floats