Flashcards in Coastal Landscape Development Deck (37)
A long, narrow ridge of land that joins to the mainland at one end and projects out into the sea / across a river estuary.
Usually on a drift-aligned coast.
Which types of coastline do spits usually form at?
Describe the formation of a spit
LSD carries material along coast -> build up of material in more sheltered water (behind headland) -> storms build up more material above HWM (permanent) -> length of ridge (spit) extends -> wave refraction / 2nd most dominant wind curves end of spit towards mainland
What feature may form behind a spit?
What factors affect the formation of a spit?
Longshore drift - wave energy, fetch.
Name the types of spits
Describe the features of a simple spit
Can be straight or recurved.
DO NOT have minor spits / recurved edges along their landward edge.
Describe the features of a compound spit
Can be straight or recurved.
DOES have minor spits / recurved edges along their landward side -> possibly marking the position where they terminated in the past
What might the minor spits / recurved edges on a compound spit show?
May mark the position where the spit terminated in the past
A spit that joins an island to the mainland
Give examples of where spits are found
Spurn Head, East Yorkshire
Sandy Hook Spit, New Jersey, USA
Give examples of where tombolos are found
Chesil Beach, UK
The Angel Road of Shodo Island, Japan
Give the factors that affect the formation of tombolos
Distance from mainland to island
Define offshore bar
Where a ridge of beach material that remains semi-submerged accumulates seaward of the breaker zone
When a spit grows across a bay and joins two headlands
What feature forms behind a bar
Lagoon (former bay)
How did some bars form after the last ice age?
The result of onshore migration of material from offshore, as sea levels rose after last ice age
By how much can bars be submerged by incoming tides?
Partially / completely submerged
Give examples of where bars are found
Slapton Ley, Devon
Chesil Beach - formed by combination of onshore migration + LSD.
Arabat Spit, Sea of Azov - longest spit in the world, joins towns in Ukrain to Crimea.
Give the factors affecting the formation of bars
LSD - wave energy, fetch
Distance from headland to headland
How has sea level changed over the past 10,000 years?
Sea level has generally been rising over the past 20,00 years.
Sea level appears to be lowering in Scotland (northwest), due to isostatic uplift of land.
Name the coastal features that form due to rising sea level
What is a fjord? Give an example
Drowned glacial valley.
Eg Sogne fjord, Norway
What is a ria? Give an example
Drowned river valley.
Eg River Dart, Devon
What is an estuary? Give an example
Drowned, shallow, lowland river valleys.
Eg Humber estuary
How do shingle beaches form?
Where sediments previously deposited on the contents shelf were above sea level.
Rising sea levels have swept up the sediment and deposited it on present day coasts.
Name the coastal features that form due to falling sea level
Raised beaches / relict cliffs
What is a raised beach / relict cliff? Give an example
Beaches and cliff lines elevated above sea level and exposed following deglaciation -> land height rises.
Eg Isle of Arran, Scotland
What is a marine platform? How does it form?
Where an expanse of gently sloping, formerly submerged land has been exposed by uplift of land / lowering sea level