Coasts Flashcards
Igneous rock examples
Granite,basalt,dolarite
Metamorphic examples
Slate,schist,marble
Sedimentary examples
Sandstone,limestone,shale
Two types of rock that make up the earths crust
Bedrock/solid geology (e.g. granite)-main mass of rock that makes up crust
Superficial geology (e.g. Boulder clay/glacier till) laid down in last 2.5 million years.
Headland/bay example
Swanage bay and Ballard point or durlston head
Dunes/psammoseres: how is it formed
Very dynamic, loose sand blown inland by onshore winds,sand trapped by debris like rock and litter, then once established vegetation helps stabilise dune by succession, each stage is called a sere.
Dune stages with plants
Final stage: climatic climax stable balance with climate and soils (dynamic equilibrium)
Plant order: Lyme grass
Marrow grass
Lichens
Pine
Berm/embryo dune/white - pioneer species colonises environment , harsh and salty to one plants can tolerate, stabilises root system/binds and traps sediment e.g LYME GRASS
Foredune/yellow/blow out - deep roots bind dune together e.g. MARROW GRASS
Grey/dune slack and wasting dunes - amount of sand reduces inland, more plants marram dies out leads to humus leads to grey e.g LICHENS
Mature dunes - heath/woodlands adapt to tolerate salt e.g PINE
What are halophytes and xerophytes?
Halophytes - salt marsh, can tolerate salt water
Xerophytes - sand dune, can tolerate dry conditions
Salt marsh/Halosere
Plant order: Algae
Cordgrass
Marshgrass
Salt grass
Muddy,salty,low energy environments. Tidal conditions bring sediments in and out and rivers bring in silt and deposits it then particles stick together get heavy and sink (flocculation)
Plant succession: Algae/eel grass - colonise,pioneer,salty conditions,silt accumulation
Then conditions change as plants adapt to spend less time submerged(Cordgrass)
Vegetation forms thick mat (Marshgrass)
Area rises above tidal influence (Saltgrass)
What is eustatic Change and isostatic change?
Eustatic change: change in sea level due to volume of water(global change) e.g. ice melting or locked up from evaporation, thermal expansion
Isostatic change: local changes in sea level due to land rising or falling e.g. ice weight causes crust to sag, but when melt isostatic rebound occurs + accretion
Terms used to describe sea level rise and fall
Rise = marine transgression,coast drowned/submergent coast
Fall = marine regression, sea bed exposed/ emergent coast
Contemporary sea level change: milankovitch cycles
Eccentricity - where earth fluctuates between a near circular orbit and elliptical orbit.more sun energy when circular> thermal expansion.
Precession - like a spinning top>influences seasons
Tilt - shaking
Spit example (hook and double)
Hook: hurst castle spit
Double: Christchurch harbour
CASE STUDY:Christchurch bay
SE coastline exposed to destructive waves,Cliffs susceptible to slumping from rising sea levels groynes at heigistbury head starve sediment and brutal storms due to long fetch. 1 M ERODED PER YEAR
CASE STUDY: Sustainable management in the maldives
Rising sea levels, constructing artificial islands, unlikely to help whole population.
Risk: money spent on artificial islands to protect capital city Malé unlike to help other isolated islands, fishing overlooked in favour of tourism, MFF (protecting mangroves which are natural defence,evacuate people).
