influences on the coastal landscape (BOOKLET 1B AND 1C) Flashcards
name the two types of waves
- constructive
- destructive
what type of waves would characterise a depositional coastline
constructive
what are the 2 ways, that the wind is able to shape the coastline in
- firstly the frictional drag, that it has on the surface of the ocean is able to create waves, which are capable of carrying out coastal marine erosion, transport and deposition
- secondly, the wind itself is able to carry out erosion, transport and deposition. These processes combine to create aeolian landforms, such as coastal dunes.
what type of waves would characterise a erosional coastline
destructive
how are wave cut platforms formed
where a Seacliff is eroded by marine action, meaning waves, resulting in the deposition of cliff material and formation of a bedrock area where erosion occurred.
what are the main sources of sediment
- fluvial inputs, from the river
- inputs from the sea
- aeolian process, carrying small amounts of sediment
what is fetch
The area in which ocean waves are generated by the wind.
why does Clacton on sea struggle to get waves, compared to somewhere like Maui in Hawaii
due it having a relatively short fetch distance, compared to that of the top surf spots
wave length =
distance from crest to crest
wave crest =
highest point of the wave
wave trough =
lowest point of the wave
swash =
movement of water, up the beach after a wave has broken
spilling breaker =
long wave length, gentle bottom slope
plunging breaker =
moderate slope, high crest and large backwash
surging breaker =
steep slope, short wave length, high wave height
why does wind allow waves to growth in size?
due to transferring its’ energy, into fluvial energy meaning that there is a larger force behind the waves
name 3 characteristic of constructive waves
- weak backwash
- low, flat waves
- pushes sediment on to the beach (causes a buildup of sediment)
name 4 characteristics of destructive waves
- strong back wash
- large steep waves
- plunges over pulling sediment of the beach
- erodes cliffs
what creates large waves
- large fetch
- large bodies of water
what is a sediment cell
A sediment cell is a largely self-contained stretch of coastline. They are regarded as closed systems as sediment is not usually transferred from one to the other. In reality, some sediment does get transferred between neighbouring cells. Each major sediment cell typically has many smaller sub-cells.
know how to calculate standard deviation
concordant
A concordant, or longitudinal type coastline occurs where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast.
discordant
A discordant coastline occurs where bands of different rock type run perpendicular to the coast. The differing resistance to erosion leads to the formation of headlands and bays.
lithology
the study of rocks. : the character of a rock formation. also : a rock formation having a particular set of characteristics.
geology
a science that deals with the history of the earth and its life especially as recorded in rocks.
what is the angle of dip
the angle of the strata (layers) in sedimentary rocks. when compared to horizontal, is important because it influences the cliff profile
why does warmer water speed up erosion
due to substances dissolving quicker meaning that more solution could be present, that could weaken the rock thus making hydraulic action and abrasion more effective.
what influences the tide
the moon
when can one expect spring and neap tides
in each lunar month one can expect 2 neap tides and 2 spring tides.
Macro tides
on the edge of large continents and seas
micro tides
on the edge of enclosed areas
what effects tidal range
- ocean size
- land formations
- the depth of the oceanic basin (how shallow or deep it is)
how does the tide effect erosion
depending on the type of tide, depends on what part of the rock is more target by erosional process
what is a closed coastal system
there is input, transfer and output of energy but not of matter. I.e. everything stays within the system
what is a open coastal system
there are, inputs, output’s of energy and matter. most environmental system are open systems
two types of coastlines
- drift aligned
- swash aligned
what is terrestrial sediment
Land-derived sediment can be provided by mass movement (e.g., rockfalls, landslides, and debris flows), especially where cliffs composed of material susceptible to such processes are being actively undercut.
what is offshore sediment
Constructive waves bring sediment to the shore from offshore locations and deposit it, adding to the sediment budget. Tides and currents do the same. Wind also blows sediment from other locations, including exposed sandbars, dunes and beaches elsewhere along the coast.
what is a positive feedback loop
A positive feedback loop occurs in nature when the product of a reaction leads to an increase in that reaction. , a positive feedback loop moves a system further away from the target of equilibrium
what is a negative feedback loop
A negative feedback decreases the amount of change by reducing some of the inputs, returning the system to stability
does the moon or the sun have more influence on the tide and why is this?
the moon, due to it being closer, causing it to have more gravitational potential
how are waves created
waves are created, by wind blowing over the surface of the water. Out to sea this creates oscillation waves which will have no forward momentum of water, only energy is transferred forward. The wave height depends on the strength and duration of the wind, the depth of the water and the length of the fetch. The fetch, is defined as the uninterrupted distance, across the ocean over which the wind blows and therefore the distance the waves have had to grow.
