Sea Level Change

Question 1

where is the fastest speed of change at a coastline found

Answer 1

at the shoreline

Question 2

over the past 2 million years what has been the cause of major fluctuations in sea level

Answer 2

glaciation

Question 3

when do our current coastlines date from

Answer 3

6000 years ago

Question 4

what are the four different time scales that Cowell and Thom identified

Answer 4

Instantaneous
Event Time scale
Engineering time frame
Geological time scale

Question 5

describe the instantaneous time scale

Answer 5

landforms are affected by changes operating in a single cycle like waves or tides

Question 6

describe event time scale

Answer 6

these operate across a time span from an individual event through to seasonal variations

Question 7

describe the engineering time frame

Answer 7

when fluctuations take place over longer time scales, from years to decades

Question 8

describe geological time scale

Answer 8

from decades to millennia

Question 9

what landforms could be affected by instantaneous, event and engineering time scales

Answer 9

instantaneous = sand beach
event= sand dunes
engineering = headlands

Question 10

list some factors that affect the rate of change at the coast

Answer 10

locations
climate
wave energy
fetch
wind speed
rock type
concordant and discordant coasts
aspect
seaward/landward dip

Question 11

why is geology a significant factor in terms in effecting the rate of change

Answer 11

it can determine the speed of erosion and the supply of sediment for deposition

Question 12

when did the last ice age end

Answer 12

around 11,500 years ago

Question 13

what is the period we are in now called

Answer 13

Holocene

Question 14

what is transgression

Answer 14

the melting of ice and the retreat of glaciers polewards led to a rise in sea level and a retreat of coastlines

Question 15

when was the last transgression in britain and what was it called

Answer 15

6000 years ago, called Flandrian

Question 16

what did Flandrian cause

Answer 16

the north sea basin and the english channel to be flooded

Question 17

what is the opposite of transgression

Answer 17

regression

Question 18

what is regression

Answer 18

something that takes place at the end of glacial periods, when sea levels fall because ice is locked up in glaciers and ice sheets

Question 19

how does tectonic activity impact sea level

Answer 19

active earthquakes or volcanos cause the crust to be displaced causing the emergence or submergence of land

Question 20

what are two other factors that impact sea level change

Answer 20

time and wind

Question 21

what is isostatic sea level change

Answer 21

when the level of the land changes

Question 22

what is eustatic sea level change

Answer 22

where the level of the sea changes

Question 23

what is causing eustatic sea level rise now

Answer 23

global warming causing the melting of ice sheets and glaciers etc

Question 24

what is glacio-eustacy

Answer 24

changes in sea level resulting from glaciation

Question 25

how do ice ages impact eustatic levels

Answer 25

in an ice age where water is frozen in ice sheets and glaciers this causes a eustatic sea level fall, but when this melts in warmer inter-glacial periods this cause eustatic sea level rise

Question 26

what was the most recent ice age called

Answer 26

Devensian glacial

Question 27

what was sea level in meters in the last ice age

Answer 27

around 100-125 m lower than today

Question 28

what did Evans in 1991 claim about how much ice could depress the land

Answer 28

that ice could depress the land beneath it by 0.3 times the thickness of the ice

Question 29

in the last ice age where was ice the thickest in Britain

Answer 29

over scotland, where isostatic readjustment is still occurring

Question 30

how much can land rise per day

Answer 30

20mm

Question 31

what is the effect of scotland still rising

Answer 31

causing parts of southern england to sink, isostatic fall

Question 32

define plate tectonics

Answer 32

the theory of the lovely of the plates that make up the earths crust

Question 33

what is orogenis

Answer 33

where at subduction zones, tectonic uplift occurs which produces fold mountains

Question 34

what is epeirogeny

Answer 34

localised tilting of the land

Question 35

what can a 1% increase in an area of the ocean cause to sea level

Answer 35

a 40 meter drop in sea level

Question 36

what process can reverse change by sea level rise

Answer 36

sea floor spreading

Question 37

what is thermal expansion

Answer 37

where rocks expand when heated and contract with when cooled

Question 38

how does thermal expansion cause sea level rise

Answer 38

when water heats up it rises

Question 39

describe a fjord

Answer 39

extremely deep steep sided drowned glacial lowland areas U shaped cross-section

Question 40

how is a fjord produced

Answer 40

formed by drowning of glacial troughs glaciers erode their valleys which create these troughs in the land, once the ice melts they’re flooded by eustatic rise

Question 41

describe a dalmatian coast

Answer 41

tigers that flow parallel to the coast formed up to 50 million years ago

Question 42

how is a dalmatian coast formed

Answer 42

where glacial valleys or normal valleys lie parallel to each other so when sea level rises and floods the valleys, the top of the valleys is left exposed

Question 43

describe a raised beach

Answer 43

far back away from the coastline former wave cut platform higher than the sea level

Question 44

describe how a raised beach is formed

Answer 44

iso static rise causing the land to rise faster than sea level

Question 45

festive a marine platform

Answer 45

gently sloping platform that was formerly submerged also known as a marine terrace slope continues far offshore

Question 46

describe how a marine platform is produced

Answer 46

when sea level rises waves move sediment underwater back and fourth which acts like a sandpaper on bedrock, which makes it flat and smooth so when sea level falls this platform emerges

Question 47

name 5 landforms created due to glacio-eustacy

Answer 47

bars, tombolos, estuaries, ria, fjord

Question 48

name two platforms causes by glacio-isostacy

Answer 48

marine platforms and raised beaches

Question 49

what is likely to be causing global warming

Answer 49

due to greenhouse gases and CO2 emissions from humans, by doing things like burning fossil fuels

Question 50

what are the two reasons for the prediction of sea level rise

Answer 50

ice is going to keep melting thermal expansion is predicted to continue

Question 51

what are some impacts of sea level change

Answer 51

flooding increased erosion loss of coastal villages power stations destroyed loss of agriculture land impact underground water sources

Question 52

what is the IPCC

Answer 52

intergovernmental panel on climate change

Question 53

what are the IPCCs projections for future sea level

Answer 53

to rise at around 4mm per year

Question 54

how much higher could sea level be by the end of the century

Answer 54

0.22 and 0.55m higher