Characteristics and formation of coastal landforms

Question 1

types of erosional landforms

Answer 1

bays & headlands
wave cut platforms
cliffs
wave-cut notches -> caves -> arches-> stacks -> stumps

Question 2

types of depositional landform

Answer 2

beaches
simple and compound spits
tombolos
offshore bars
barrier beaches
coastal dunes
tidal sedimentation in estuaries: coastal saltmarshes
mangroves

Question 3

two types of coastline:

Answer 3

concordant
discordant

Question 4

what type of coastline has bays and headlands

Answer 4

discordant

Question 5

what is a discordant coastline

Answer 5

is in disagreement with the geology of the coastline
Purpendicular to the geology

Question 6

what is a concordant coastline

Answer 6

parallel to the lithology of the coastline

Question 7

formation of wave-cut platforms

Answer 7

a flat rock area in the intertidal zone created by destructive waves concentrating its energy on the base of the cliff causing it to erode leaving an overhang which will become unstable and drop onto the platform. This sediment is then carried out into the sea with the tides

Question 8

erosion of a headland

Answer 8

cracks in the intertidal zone become exposed by hydraulic action
cracks are widened to become wave-cut notches
wave refraction causes destructive waves to concentrate their energy on the sides of the headland, creating caves
if aligned these will create arches
over time the arch will become unstable and will drop, creating a headland and a stack
the stack will be eroded and weathered, then becoming a stump

Question 9

what are the two types of beach

Answer 9

swash and drift aligned

Question 10

swash aligned beaches are…

Answer 10

formed in low energy environments, in bays, with a large beach profile often with berms and sand dunes

Question 11

drift aligned beaches require….

Answer 11

a regular supply of sediment to sustain them. without human management these lead to the formation of spits, bars, tombolos and barrier islands

Question 12

features of a beach (sea to sand)

Answer 12

ridges and runnels
ripples
cusps
berms
storm beaches

Question 13

what are berms

Answer 13

low hills of sand or gravel that forms at the upper limit of the swash. They
are short-term features and are removed by successive tides and storms

Question 14

what are cusps

Answer 14

crescent-shaped embayment developed on beaches of mixed sediment, formed where sand meets shingle

Question 15

what are simple spits

Answer 15

a long SINGULAR narrow extension of sand or shingle which has one end attached to the coastline and one out into the sea, formed by longshore drift

Question 16

what are recurved spits

Answer 16

those shaped by the effects of tides or local changes in wind direction

Question 17

what are compound spits

Answer 17

those with multiple protrusion from the spit, often from storms

Question 18

what are tombolos

Answer 18

when spits extend from a coast to an island

Question 19

howare esturane mudflats created

Answer 19

created by flocculation in sheltered low energy coastlines

Question 20

what are saltmarshes

Answer 20

mudflats with the addition of vegetation, areas of flat silty sediments around esturies or lagoons

Question 21

list the three environments which saltmarshes can form in

Answer 21

sheltered areas where deposition occurs
where salt and fresh water meet
where there are no strong tides or currents to remove deposited silts

Question 22

salt marsh succession:

Answer 22

starts below high tide
only needs a loss of energy for flocculation to occur
pioneer species grow between high and low tide (sward zone)
gradually mud rises above high tide and the low marsh develops
soil conditions improve and meadows are formed
climatic climax is reached in the uplands

Question 23

threats to saltmarshes

Answer 23

sea level rise
development along a coastline
storms

Question 24

sand dune development

Answer 24

sand bounced along the beach by saltation
trapped by physical obstacles e.g driftwood
embryo dunes are suitable for colonisation of pioneer species
these provide stability, binding the sand together to create foredunes/mobile dunes
as more plants grow these become fixed dunes
over time dunes mature and reach climatic climax

Question 25

dune slacks
vs
creeks

Answer 25

near the water table on a sand dune

develop to remove water, within the intertidal zone

Question 26

why are mangroves important

Answer 26

important for ecosystems and wildlife such as the manatee, lizards and Bengal tigers
natural coastal protection from storm surges, coastal erosion and

Question 27

characteristics of mangroves:

Answer 27

found in tropical and sub-tropical areas
between 20degrees N-S
found along the coasts of Africa, Australia, Asia and the Americas

Question 28

conditions required for mangrove growth

Answer 28

permanently waterlogged soil
in areas with a limited supply of freshwater
hot weather
intense sunlight
gently sloping coastline with mudflats

Question 29

the values of mangroves

Answer 29

ocean tsunami of 2004, where the mangroves had been removed 6000 died, only 2 deaths where they still were

tourism provides 75% GDP

Question 30

threats to mangroves

Answer 30

human clearance - tourist development
agricultural land
settlement
infrastructure
overfishing
pollution
climate change

Question 31

UN figures on mangrove clearance

Answer 31

estimates 20% lost since 1980. Thailand lost 50% since 1960 and Philippines 70% since 1920