Coasts: Key Terms Flashcards
abrasion
a process of erosion in which waves chip away at the rock by hurling sand and pebbles at the base of the cliff when they break
arch
when two. aves are eroded on either side of a headland or a single cave is eroded through a headland, an arch is formed
attrition
a process of erosion in which angular rock fragments are smoothed and reduced in size forming pebbles, shingle and sand due to friction
barrier beach / bar
a long, narrow ridge of sediment extending across a bay to join two headlands together, forming a lagoon behind it.
barrier island
a berried beach that has been separated from the mainland to form an / a series of islands.
berm
a ridge or plateau on a beach marking a high tide line, formed by the deposition of beach material from constructive waves
cave
A cliff profile feature formed when hydraulic action exploits a weakness in the cliff and enlarges and undercuts it.
Coastal morphology
the origin and evolution of a coast
compound spit
a long, narrow ridge of deposited sediment which is joined to the mainland at one end and sticks out into the sea across an estuary or bay. They have a series of minor spits or recurred ridges along their landward edge, showing their former position.
constructive wave
waves that build up the beaches. they are low in height and frequency and long in wavelength. they have a large swash.
destructive wave
waves that remove the beach material along the shoreline. they are steep in height, short in frequency and high in energy. They have a short lived swash and a forceful backwash.
cusp
crescent-shaped beach formation with graded sediment on the edge of the lowest berm.
corrasion
a process of erosion where as waves advance, they pick up sand and pebbles from the seabed. When they break and the foot of a cliff, the transported material is hurled at the base of the cliff, chipping away at the rock.
high-energy environments
a costal environment that experiences strong waves and winds and has a long fetch. the rate of erosion is larger than the rate of deposition and there is a net transfer of material from coast to sea.
hydraulic action
a process of erosion in which waves break against a rock face and compressed air into the cracks, creating pressure within. As the water pulls back there is an explosive effect of the air under pressure being released.
landform
individual components of a landscape e.g cliffs, beaches, arches
landscape
landscapes are made up of a number of landforms which give them their key characteristics.
low-energy environments
a coastal environment with less powerful waves and weak onshore winds. the rate of deposition is greater than the rate of erosion.
mass movement
the movement of martial downhill under gravity, often assisted by rainfall.
recurred tip
where the end of a spit curved round towards the land as wave refraction carries the material round into the more sheltered water behind the spit.
rip currents
strong localised underwater currents that occur in some beaches and move water away from the shoreline
runnels
the dips in the foreshore area of a beach between ridges. they are drained down by the beach by to channels that break the ridges.
saltation
a method of transportation where small stones bounce along the seabed and beach. this process is associated with high energy conditions. as the particles land the may dislodge others.
sediment budget
the balance between sediment added to and removed from the coastal system.
sediment cell
a stretch of coastline within which sediment is largely recycled, maintaining a state of relative balance.
solifluction
a method of transportation where dissolves materials are transported within the mass of moving water. this form of transportation plays an important role in the carbon cycle, transferring and depositing carbon in the oceans.
solution (corrosion)
a process of erosion in which some calcium-based rock e.g chalk and limestone is readily soluble and dissolved minerals can then be removed in solution.
spit
a long, narrow ridge of deposited sediment which is joined to the mainland at one end and sticks into the sea or across and estuary or bay. A simple spit is either straight or recurred but doesn’t have minor spits or recurred ridges.
suspension
a method of transportation where very small particles of sand and silt are carried along by the moving water within the flow. suspension is most likely to occur where flow is turbulent.
tidal range
the relative difference in height between high and low tides
tides
changes in the water levels of seas and oceans caused by the gravitational pull of the moon and (to a lesser extent) the sun.
tombolo
ridge of beach material formed between the island and the mainland
traction
a method of transportation where large stones and boulders are rolled along the seabed and beach by moving seawater. they are too heavy to be picked up and carried and with only move if energy levels are high enough.
wave refraction
when waves bend as they approach a coastline that is indented, becoming increasingly parallel to the coastline.
isostatic sea level change
a change in the level of the land relative to the sea as a result of the changing level of the land.
eustatic sea level change
a rise or fall in the sea level as a result of a change in the actual level of water in the oceans.
biological weathering
the breakdown of rocks by organic activity, including vegetation and coastal organisms
drift-aligned beach
a beach formed where the waves approach the coast at an angle.
eustatic change
when the sea level itself rises or falls
isostatic change
when the land rises or falls relative to the sea.
isostatic recovery
when the ice beginning to melt at the end of a glacial period, causes the land to readjust and rise due to the reduced weight of the ice
isostatic subsidence
when the enormous weight of ice sheets makes the land sink during glacial periods
offshore bars
submerged ridges of sand or coarse sediment created by waves offshore from the coast
pioneer species
the first colonising plants in a vegetation succession
fjord
A submergence coastal landform formed when a rise in sea level floods a deep glacial trough
raised beach
an emergent coastal landforms which is the results of isostatic recovery which raises beaches above the present sea level
ria
a submergence costal landform composed of shelter winding inlets with irregular shorelines formed from flooded river inlets
Dalmatian coast
a submergence landscape of ridges and valleys running parallel to the coast
saltmarsh
coastal ecosystem formed on mudflats largely comprising salt-tolerant plants
swash-aligned beach
a beach formed in a low-energy environment by waves roughly parallel to the shore
rockfall
sudden mass movement where fragments of rock break away from a cliff face as a weakness becomes unsupportable, associated with steep cliffs in well-jointed, resistant rock.
landslide
blocks of rock slide downhill, occurring on cliffs made from softer rocks running parallel to the slide plane
mudflow
sudden mass movement where fine particles of mud flow down a slope, saturated by persistent rainfall
slumping
whole sections of cliff face moving downward along a concave slide plane, producing a rotational movement
soil creep
the gradual movement downhill of individual soil particles, resulting in terracettes on slopes
longshore drift
a process of littoral movement where the wind causes the swash to carry sediment up the beach at an angle, and the brackish pulls material back down perpendicular to the shore, causing a zigzag movement of sediment up and down the beach.
