3.1-coastal landscapes and systems Flashcards
resistant rock coastlines:
cornwall’s rocky coastline can withstand winter storms without suffering rapid erosion.
like the rest of western and northern britain, much of cornwall consists of older rocks that are resistant to the erosive power of the sea, including:
-igneous rocks (e.g. granite)
-older compacted sedimentary rocks (e.g. old red sandstone)
-metamorphic rocks (e.g. slates and schists)
coastal plain landscapes:
britain’s eastern and southern coasts consist of areas of younger, much weaker sedimentary rocks (including chalks, clays, sand and sandstone).
-the wash is an area of low, flat relief, referred to as a coastal plain.
-much of the coast of eastern england consists of low lying sandy beaches, e.g. skegness on the lincolnshire coast.
high energy coastlines:
rocky coasts are generally found in high energy environments. in the uk, these tend to be:
-stretches of the atlantic facing coast (with powerful waves)
-where the rate of erosion exceeds the rate of deposition.
erosional landforms are found in these environments.
low energy coastlines:
sandy and estuarine coasts are generally found in low energy environments. in the uk, these tend to be:
-stretches of coast where waves are less powerful or where it is sheltered
-where the rate of deposition exceeds the rate of erosion.
depositional landforms are found in these environments.
the coast as a system:
the coast is constantly changing, so it helps to think of it as a system driven by wave energy.
inputs~
-marine: waves, tides, storm surges
-atmospheric: weather/climate, climate change, solar energy
-land: rock type and structure, tectonic activity
-people: human activity, coastal management
processes~
-weathering
-mass movement
-erosion
-transport
-deposition
outputs~
-erosional landforms
-depositional landforms
-different types of coast
the littoral zone:
the littoral (coastal) zone stretches into the sea and onto the shore. it is constantly changing because of the dynamic interaction between the processes operating in the seas and on land, it varies because of:
-short term factors (e.g. waves, tides, storms)
-long term factors (e.g. changes to sea level, climate change)
the littoral zone consists of sections. the backshore and foreshore are where most human activity occurs and where most physical processes (erosion, deposition, transport and mass movement) operate.
sediment supply:
the processes of weathering and erosion produce sediment, which is transported and deposited to produce coastal landforms. in the wash, sediment originates from:
-cliffs eroding between west runton and weybourne
-tidal currents, which pick up glacial deposits from the shallow sea floor
-erosion of the holderness cliffs, sediment is carried southwards in suspension
-sand carried southwards along the lincolnshire coast
-rivers discharging into the wash
classifying coasts:
coasts can be classified depending on:
-geology~creating rocky, sandy and estuarine coasts, plus concordant and discordant coasts
-the level of energy~creating high or low energy coasts
-the balance between erosion and deposition~creating either erosional or depositional coasts
-changes in sea level~creating emergent or submergent coasts
lithology:
*strata- a layer or series of layers of rock in the ground.
*bedding planes- a surface representing a contact between a deposit and the depositing medium during a time of change.
*joints or cracks-a brittle-fracture surface in rocks along which little or no displacement has occurred.
*folds-a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation.
*faults-a fracture or zone of fractures between two blocks of rock. faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep.
*dip-the angle at which a planar feature is inclined to the horizontal plane.
