Coasts Flashcards
Give an example of an emergent and submergent coastline?
emergent - Scottish coastline near earlsferry in fife
submergent - south coast of England and the east coast of America
Give the definition of a ria and a fjord?
Ria - a drowned river valley in an unglaciated area caused by sea level rises flooding the river valley, making it much wider than would be expected based on the river flowing into it.
Fjord - a long, narrow, deep inlet of the sea between high cliffs, as in Norway, typically formed by submergence of a glaciated valley.
What are some characteristics/landforms associated with both emergent and submergent coastlines ?
emergent- cause the formation of raised beaches and fossil cliffs caused by isostatic rebound
submergent - most common coastal feature is a ria and a fjord and also cause Dalmatian coasts
What are the words for sand dune ecosystem and salt marsh ecosystem?
a sand dune ecosystem = psammosere
a salt marsh ecosystem = halosere
What is a Dalmatian coast?
A concordant coastline with several river valleys running perpendicular to the coast. They become flooded to produce parallel long islands and long inlets
When talking about dams that cause erosion give two examples and the year that it affected erosion rates and some facts about each one?
Aswan high dam on the river Nile and in the 1960s river discharge fell from about 35 billion m cubed to 10 billion metres cubed and sediment volume fell from 130 million tonnes to 15 million tones. The Nile delta now did not have the natural protection of sediment
Akosombo dam in Ghana in 1965 reduced the flow of sediment down the river Volta from 70 million metres cubed to less than 7 million metres cubed, with major impacts on longshore drift and coastal erosion in Ghana and even neighboring countries
Briefly explain the difference between faults joints folds, bedding planes and fissures?
Faults = Major fractures in the rock produced by tectonic forces and involving the displacement of rocks on either side of the fault line
Joints are vertical and bedding planes are horizontal and they divide up rock strata into regular patterns
Fissures = often smaller cracks in the rock only a few centimetres/ millimetres long, but they represent weaknesses that erosion can exploit.
Folds = Folding occurs due to crustal compression, this is where the rock buckles under each one due to the exceeding amount of pressure on it
Give examples of where you may find low - energy coasts and where you may find high energy coasts?
Low energy coastlines are prominently situated on the west coast of the UK with examples including Bamburgh in Northumberland and Norfolk
High energy coasts would be on the east coast of the UK with an example being the Bedruthan steps in Cornwall.
What are the 3 ways we can classify a coastline?
- Level of energy - Low/High energy coasts
- Tidal range - micro/meso/macro
- ## Relative sea level - Emergent coasts/ Submergent coasts
What places can be said to have a high coastal flood risk ?
- Coastal plains
- estuaries such as river Thames
- River deltas, such as the Nile and Mississippi
Talk about Kiribati and the problems it is facing.
Kiribati is a small island located just off papa new guinea and is severely under threat of sea levels rising
Kiribati’s islands are very low lying and mangrove atolls with most of the island only 1 metre or less above sea level
Kiribati’s population will likely be environmental refugees as it said due to sea level rising the island of Kiribati could be submerged within 50 years
In a ice age when the land is covered in ice what do we call a drop in land height?
- Crustal sag
This is due to the weight of the ice
Where might we see post isostatic rebound ?
Scotland as that was a place that was submerged under a lot of ice in the ice age.
Give some examples of hard engineering and soft engineering techniques?
Hard engineering
- Sea wall
- Revetments
- Rock Armour
- Groynes
Soft engineering
- Beach nourishment
- Sand dune stabilization
- cliff stabilization
What are two aspects that are dominant in influencing cliff profiles?
1) The resistance erosion of the rock
2) The dip of rock strata in relation to the coastline
What is a swell waves?
The wind that has caused the waves has dropped but the remaining waves gradually make their way onshore
What is plant boring ?
Many species of clams and molluscs bore into rock and may also secrete chemicals that dissolve rocks.
What term describes how wave energy is lost due to friction with the beach?
Dissipation
Over longer periods of time how may beach profiles change?
- Sediment supply from rivers is reduced
- Interference in sediment supply along the coast, often a result of coastal management in one place affecting another place further along the coast
- Changes to climate for example global warming
When talking about the Sub-aerial process of weathering what does in-situ mean?
in-situ = the original place
Whats the difference between the terms ;
- Bayhead beach
- Barrier beach
Bayhead beach = a beach at the head of a bay
Barrier beach = barrier beaches are narrow, low-lying strips of beach and dunes that are roughly parallel to the coastline and are separated from the mainland by a body of water or wetland
What are the sand dune stages?
- Embryo Dune
- Fore Dune ————- Mobile Dunes
- Yellow Dune
- Grey Dune
- Dune slacks ————- Fixed Dunes
- Succession
What are the two types of Storm Surges?
- A depression for examples the UK
- A tropical cyclone (hurricane, typhoon)
What are some of the island that are under the threat of environmental refugees?
Maldives, Tuvalu, Barbados
What are some facts when talking about Contemporary sea level change?
- The Intergovernmental Panel on Climate Change (IPCC) estimated increases in sea level of 20-50cm by 2100
- The current rate of rise is 2mm per year
How many SMPs are there in England and Wales ?
- 22
What are the three main types of soft coastal engineering ?
- Beach nourishment
- Cliff stabilisation
- Dune regeneration
What does the key term Outflanking?
Outflanking = Occurs when erosion gets behind coastal defenses at the the point where they stop, leading to rapid erosion inland and undermining of defenses
This may become an issue at the high risk location of Mappleton
What type of rocks are most vulnerable to rotational slides?
- where there is permeable strata (chalk, sandstone) sit on top of impermeable strata. This is common in areas like the south of england and can be found at Folkestone
How are tides produced as?
- Produced as a bulge of water rotates around locations in the ocean called amphidromic points. As the bulge passes a location on the coast, high tide occurs - twice a day with roughly 12- hour interval
