Emergent Landforms

Question 1

What is a raised beach?

Answer 1

=area of former shore platform/beach that is left at higher levels than current SL

Question 1

2 main causes of sea level change

Answer 1

1. Decrease global temperature-> more precipitation in form of snow, compacts to ice-> reduce the volume of water in the ocean store => SL decrease
2. global warming- melting of ice sheets and thermal expansion of water as it warms
3. earthquakes= vertical movement either sides of faults leads to increase or decrease in sea level
   -thousands of years and only a few metres => NOT SIGN

Question 2

example of raised beach

Answer 2

Scotland/isle of portland, dorset- formed 125,000 years ago

Question 3

how is a raised beach formed?

Answer 3

1. shaped during high SL where HA and abrasion from wave action eroded cliff face -> shore platform during inter-glacial periods (similar to now)
2. Sediment from cliff face deposits as SL falls=> builds up platform so it isn’t flooded over, now exposed
3. New material constantly added to create a present day storm beach.
   -weathering weakens rock structure/breaks down rock types to alter features
   -continual static change means present day beach covered at high tide and active cliff above erodes, decreasing size of raised beach terrace
   - mass mov. retreat cliff but usually LONG TERM CHANGES On a fairly small scale

Question 4

what is an emergent landform?

Answer 4

= landforms shaped by wave processes during times of high sea level, left exposed when SL falls, can be found inland at a distance
- after emerging, no longer affected by wave processes
-due to isostatic rebound of land

Question 5

EUSTATIC CHANGE?

Answer 5

= Worldwide rise and fall in sea level
GLOBAL SCALE from melting ice sheets and increase global temp.

Question 6

ISOSTATIC CHANGE

Answer 6

=Changes in the level of land - REGIONAL/LOCALISED from tectonic activity and glaciers melting => land rebounds back up

Question 7

What is a marine terrace?

Answer 7

=old shore platform shaped by erosion and deposition over thousands of years

Question 8

Relict cliff?

Answer 8

= one no longer eroded by sea due to isostatic and eustatic change

Question 9

How is a marine terrace formed?

Answer 9

1. increase in land height due to isostatic rebound -> shore platform exposed
2. repeat this process over many years-> shore platforms at different heights
3. old platform affected by biological and freeze-thaw weathering => cliff is at 40* and less steep, vegetation growth as well
4. natural SL decrease exposes wave-cut surfaces, often multiple terraces due to isostatic change OVER THOUSANDS OF YEARS.
   -chemical weathering (carbonation of limestone) very influential
   -thawing of permafrost in subsoil during last glacial period

Question 10

what happens to emergent landforms if SL rises enough?

Answer 10

• found closer to coast
• may be subject to wave processes again