edexcel a level geography -Coasts Key terms

Littoral zone

Is the wider coastal zone including coastal land areas and shallow parts of the sea just offshore.

Subaerial processes

Includes weathering processes (mechanical, chemical and biological), mass movement (landslides, rock falls) and surface runoff erosion.

Accretion

Refers to the deposition of sediment at a coast that expands the area of land.

Wave refraction

Is the process causing wave crests to become curved as they approach a coastline.

Anticlines and Synclines

Are types of geological fold caused by tectonic compression.

Anticlines form crests.

Synclines form troughs.

Cliff Profile

Is the height and angle of a cliff face, plus its features such as wave-cut notches or changes in slope angle.

Faults

Are major features in rocks produced by tectonic forces and involve displacement of rocks on either side of the fault line.

Micro-features

Are small scale features such as caves and wave-cut notches whi9ch for part of a cliff profile.

Clastic Rocks

Consist of sediment particles cemented together.

Crystalline Rocks

Are made up of interlocking mineral crystals.

Pore water pressure

Is a internal force with cliffs exerted by the mass of groundwater within permeable rocks.

Plant succession

Means the changing structure of a plant community over time as an area of initially bare sediment is colonised.

Fetch

Is the uninterrupted distance across water over which a wind blows and therefore the distance waves have grown in size.

Swash

Is the flow of water up a beach with a breaking wave.

Transports sediment

Backwash

Is the water draining down the beach back into the sea.

Transports sediment.

Beach Morphology

Means the shape of a beach, including its width and slope (beach profile) and features such as berms, ridges and runnels.

It also includes the type of sediment (shingle, sand, mud) found at different locations on the beach.

Longshore drift

Is the net transport of sediment along the beach as a result of sediment transport in the swash and backwash.

Weathering

Is the in situ breakdown of rocks by chemical, mechanical or biological agents.

It does not involve any movement.

Mass movement.

Refers to the downslope movement of rock and soil. It is an umbrella term for a wide range of specific movements including landslides, rockfall and rotational slide.

Post-glacial adjustment

Refers to the uplift experienced by land following the removal of the weight of the ice sheets.

Rias

Are drowned valleys in unglaciated areas, caused by sea level rise flooding up the river valley, making it much wider than would be expected based on the river flowing into it.

Barrier islands

Are offshore sediment bars, usually sand-dune covered, but unlike spits they are not attached to the coast.

They are found between 500m and 30Km offshore and can be tens of kilometers long.

Thermal expansion

The main driver of sea level rise, occurs because the volume of ocean water increases as global temperatures rise.

Dredging

Involves scooping or sucking up sediment from the sea bed or a river bed.

Dissipation

Is the term used to describe how the energy of waves is decreased by friction with beach material during the wave swash up the beach. A wide beach slows waves down and saps their energy so when they break, most energy has gone.

Storm surge

Is a localised, short-term rise in sea level caused by air pressure change : a 1 millibar fall in air pressure leads to a 1cm rise in local sea level.

Amenity value

Is the value in cultural, human wellbeing and economic terms of an attractive environment that people enjoy using.

Environmental refugees

Are communities forced to abandon their homes because of natural processes, including sudden ones such as landslides or gradual ones such as erosion or rising sea levels.

Sustainable coastal management

Means managing the wider coastal zone in terms of people and their economic livelihood, social and cultural wellbeing, safety from coastal hazards, as well as minimising environmental and ecological impacts.

ICZM

Is the coastal management planning over the long term, involving all stakeholders, working with natural processes and using ‘adaptive management’ E.g. changing plans as threats change.

Conflict

In the context of coastal management means the disagreement over how the coast should be protected from threats and which areas should be protected. Often conflict exists between different stakeholders, such as residents vs the local council.

Littoral cells

Contain sediment sources, transport paths and sinks. Each littoral cell is isolated from adjacent cells and can be managed as a holistic unit.