Coasts Flashcards

Question

Eustatic Change

Answer 1

The change of sea level relative to the land. The change is global in scale. Global sea levels can be thought as a system that depends on relative rates of inputs and outputs. Falls due to freezing.

Answer 2

The vertical difference in height between consecutive high and low waters over a tidal cycle.

Answer 3

Includes processes at the base of the atmosphere that slowly breakdown the coastline, weaken the underlying rocks and allow sudden movements or erosion to happen more easily - weathering, mass movement and run-off.

Answer 4

The first plant species to colonise an area. It is well adapted to living in harsh environments.

Answer 5

Tides are caused by slight variations in gravitational attraction between the Earth and the moon and the Sun in geometric relationship with locations on the Earth's surface.

Answer 6

Low-lying areas of the shore that are covered at high tide and when uncovered at low tide a stretch of muddy land composed of silt and clay are left.

Answer 7

1) Circular orbit in open water 2) Friction slows down base of the wave 3) Wave becomes more elliptical in movement 4) Top of wave moves faster. Becomes increasingly elliptical 5) Wave begins to break 6) Water rushes up the beach as swash 7) Water from previous wave returns as backwash

Answer 8

Coastlines composed of chalk or limestone may be dissolved by acidic rainwater or seawater. The rain/sea absorbs carbon dioxide from the atmosphere, creating a weak carbonic acid. This can convert solid calcium carbonate to soluble calcium bicarbonate and the rock dissolves.

Answer 9

Swell: waves formed by distance storms that travel a long distance. Sea: waves formed by local winds and travel only short distances.

Answer 10

The gradual movement downhill of individual particles due to gravity. Raindrops or wave splash may dislodge a particle, and it is most likely to take a downwards trajectory due to the influence of gravity.

Answer 11

An elongated bank of deposited sand or shingle lying parallel to the coastline and not submerged by incoming tides. Where the bank is high enough to allow sand dunes to develop it is known as a barrier island. They tend to develop where the coast has relatively high energy waves, small tidal range, gentle gradients offshore and plentiful supply of sediment.

Answer 12

Arch roofs, stacks and cliff faces collapse as a weakness becomes unsupportable.

Answer 13

- Discordant coastlines - Alternating bands of hard and soft rock - Less resistant soft rock gets eroded quicker - Headlands left sticking out and eventually collapse as they're unsupported as vulnerable - Bays form from rapid erosion from soft rock

Answer 14

Traction: rolls along seabed Saltation: bounce along seabed Suspension: carried along seabed Solution: dissolved

Answer 15

At an angle from the angled prevailing winds. Therefore swash is at an angle and the backwash comes down from the force of gravity. The process repeats itself and transports sediment across the coastline.

Answer 16

When high energy, tall waves hit the cliff face they have the power to enlarge joints and remove large chunks of rock in one go through vibration. This occurs due to the intense force of these waves.

Answer 17

When sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs are prone to this type of erosion.

Answer 18

When rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.

Answer 19

When pebbles grind along a rock platform, much like sandpaper. Overtime, the rock becomes smooth.

Answer 20

The sheer power of the waves as they smash against the cliff. Air becomes trapped in the cracks in the rock and causes the rock to break apart.

Answer 21

Water is running off the land. E.g. a stream across a bay or over a cliff

Answer 22

Material is removed from one location to another Traction, saltation, suspension, solution

Answer 23

- Develop as a result of eustatic sea level rise or isostatic descent - Rias, fjords, dalmation coasts

Answer 24

Degradation of rock and its removal to expose a fresh rock face. Hydraulic action, abrasion, attrition, solution, wave quarrying

Answer 25

Operate along the coastline and are connected with the sea, such as waves, tides and longshore drift: erosion, transportation and deposition.

Answer 26

Dry rock in the sun may absorb considerable heat, then be cooled rapidly by contact with the much cooler sea. Repeated expansion and contraction may lead to the outer layers of rock fracturing.

Answer 27

A coastal fixed or tsunami-like phenomenon of rising water commonly associated with low pressure weather systems, such as cyclones. It is measured as the rise in water level above the normal tidal level and does not include waves.

Answer 28

Surface animals may excavate nesting burrows in cliff faces. Subsurface marine creatures such as the piddock drill holes in rock and limpets create a home indentation on their base rock to which they return after grazing.

Answer 29

Natural mechanisms that result in the modification of the surficial materials and landforms at the Earth's surface.

Answer 30

A sequence of vegetation species colonising an changing an environment.

Answer 31

The high salt content of seawater can lead to the growth of salt crystals within rock under drier conditions. These can exert pressure within small joints and, overtime, cause the rock to lose integrity.

Answer 32

- Low energy environment and shelter from winds and waves - Large inout of sediment - Coastal accretion reduces flooding and allows plants to grow - Glasswort, cordgrass (pioneer species) grow - More plants colonise marsh, red fescue - Deepen, only highest tides - Sea lavender - Halosere

Answer 33

When a spit extends from a shore and reaches an offshore island. E.g. Onesil Beach, Dorset

Answer 34

The shape and make-up of the beach Dependent on several factors: - Wave type - Energy - Sediment type - Sea bed morphology

Answer 35

- Rocks on land - Volcanoes - Streams or rivers flowing into seas - Estuaries - Cliff erosion - Offshore banks - Material from biological origin, shell fragments, coral fragments

Answer 36

When a spit extends across a bay and rejoins the coast on the opposite shore, completely confining salt water behind it in a lagoon. Some bars form by onshore migration if material deposited offshore as sea levels rose after the last ice age. E.g. Slapton Ley, Devon

Answer 37

Rocks containing iron compounds experience oxidation of the iron into a ferric state (or 'rusting') when oxygen and water are readily available from air or sea. This can lead to disintegration.

Answer 38

Where a ridge of beach material that remains semi-submerged accumulates seaward of the breaker zone then it is called an offshore bar. They form from sediment eroded by destructive waves and carried seawards by backwash.

Answer 39

Makes rocks more susceptible to further chemical weathering, although involves addition of water to minerals in the rock. This causes the rock to expand, creating stress, which can itself cause the rock to disintegrate. The process weakens the rock and can create cracks or widen joints allowing further chemical weathering to occur.

Answer 40

A length of coastline within which the movement of coarse sediment is largely self-contained. They are separated from other areas by well-defined boundaries, such as headlands and stretches of deep water.

Answer 41

Rock in the intertidal zone may alternate between being wet and being dry. Some rocks expand when they are wet and contract dry, and this can contribute to tiny cracks developing and the rock fragmenting.

Answer 42

Fine particles of mud flow down the face of cliffs, often heavily saturated by persisted rainfall which adds to its bulk and makes it a more liquid consistency.

Answer 43

- Can be caused as a result of eustatic fall in sea level or isostatic rise or a combination of both - Raised beaches, relict cliffs

Answer 44

A succession of rational landslips in which the cliff face collapses in distinct stages. Heavy rain may lubricate a curved slip plane and undercutting at the cliff base by wave action results in a slippage of material down towards the beach. It often occurs on cliffs composed of glacial deposits.

Answer 45

A succession beginning in a sandy environment.

Answer 46

The movement of cold water from deep in the ocean towards the surface. The more dense cold water and creates nutrients rich cold ocean currents. These currents form parts of the pattern of global ocean circulation currents.

Answer 47

- Wind speed (the higher the wind speed the greater the energy) - Fetch (the longer the fetch the greater the energy) - Solar energy - Length of time the wind has been blowing - Variability of wind direction (prevailing winds generate more high energy waves than conditions where the wind direction is constantly shifting) - Pressure gradients (low pressure will generate stronger winds and more high energy waves)

Answer 48

Where mildly acidic water reacts or combines with minerals in the rock to create clays and dissolvable salts; this itself degrades the rock, but both are likely to be weaker than the parent rock, this making it more susceptible to further degradation.

Answer 49

The movement of consolidate material (solid rock) or unconsolidated material (clay and soil) due to gravity. Rockfall, landslides, mudflows, soil creep, rotational slip/slumping

Answer 50

- Wave steepness and breaking point - Fetch - Sea depth - Coastal configuration e.g. convergent energy at headlands - Beach - Human activity - Geology

Answer 51

Higher-energy destructive waves during the stormier winter months as there is low pressure and more storms. Constructive lower-energy waves are during the calmer summer months.

Answer 52

The sea deposits its loads when it looses energy or there is an increase in the amount of eroded material.