Coastal Landscapes & Change Vocabulary List

Littoral zone

The area of shoreline where land is subject to wave action

Offshore

The area of deeper water beyond the point at  which waves begin to break

Nearshore

The area of shallow water beyond the low tide mark

Foreshore

The area between the high tide and the low tide mark

Backshore

The area above the high tide mark

Rocky coastline

Areas of high relief varying from a few metres to hundreds of metres in height, with resistant geology & high energy

Sandy coastline

Areas of low relief with sand dunes and beaches, that are much flatter, with less resistant geology & high energy

Estuarine coastline

Areas of low relief with salt marshes and mudflats, at river mouths in a low energy environment

Eroding coastline

Where erosion exceeds deposition: there is a net loss of sediment and the coastline retreats

Outbuilding coastline

Where deposition exceeds erosion there is a net gain of sediment and the coastline advances

Lithology

Physical properties of a rock (rock type)

Weathering

The breakdown of rock *in situ*

Erosion

The breakdown of rock and its immediate transport by the eroding agent

Mass movement

The downslope movement of material due to the force of gravity

Coastal accretion

Where continuous net deposition causes the coastline to extend seawards

Concordant coastline

Coasts that form where rock strata run parallel to the coast

Discordant coastline

Coasts that form where rock strata are aligned at an angle to the coastline

Geological structure

The characteristics and arrangement of rock units

Strata

Different layers (or beds) of rock

Bedding plane

The interface between two sedimentary strata

Deformation

The degree of tilting of folding of rock

Dip

The angle of inclination of titled strata

Faulting

The fracturing of rock with movement from its original position

Joint

A fracture of rock without movement from the original position

Morphology

The shape of landscape features, influenced by geological structure

Folds

Bends in rocks produced by sedimentary rock layers being squeezed by tectonic forces

Cliff profile

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

Micro-features

Small-scale coastal features such as caves and wave-cut notches which form part of a cliff profile

Rate of recession

The speed at which the coastline is moving inland

Clastic rocks

Rocks made of sediment particles cemented together

Crystalline rocks

Rocks made of interlocking mineral crystals

Igneous rocks

Rocks formed from solidified lava or magma

Metamorphic rocks

Rocks formed by the recrystallisation of sedimentary and igneous rocks through heat and pressure

Sedimentary rocks

Rocks formed by the compaction and cementation of deposited material, or sediment

Unconsolidated sediment

Sediment that has not yet been cemented to form solid rock

Drift geology

Recently deposited unconsolidated sediment that usually overlies the solid geology of the bedrock

Permeable rocks

Those that allow water to flow through them, due to being porous or having numerous joints

Pioneer plants

The first plants to colonise freshly deposited sediment

Plant succession

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

Climax community

The end result of a plant succession

Xerophytic plants

Plants that are specially adapted to dry conditions to colonise bare sand

Psammosere

Plant succession on sand

Embryo dunes

Form when seaweed, driftwood or litter provides a barrier or shelter to trap sand

Yellow dunes

Form when marram grass colonise sand, have a sandy surface

Grey dunes

Form when marram grass & sedge grass dries, adding hummus to the sand; are fixed

Halophytic plants

Plants that are specially adapted to saline conditions to colonise mud

Halosere

Plant succession in salty water

Flocculation

When clay particles stick together and sink

Dune blowouts

Gaps created when storm events erode sections of the yellow dune through wind or wave action

Wave

The transfer of energy from one water particle to its neighbour with individual water particles moving in a circular orbit

Wave height

Vertical distance from peak to trough

Wavelength

The horizontal distance from crest to crest

Wave frequency

The number of waves passing a particular point over a given period of time

Fetch

The uninterrupted distance across water over which the wind blows

Constructive waves

Low energy waves with a strong swash, depositing sediment

Destructive waves

High energy waves with a strong backwash, eroding sediment

Swash

The name given to the waves that rush up the beach after a wave has broken

Backwash

The name given to the water that runs down the beach after the swash

Beach morphology

The shape of the beach

Sediment profile

The pattern of distribution of different sized or shaped deposited material

Berm

A ridge of material across the beach

Shingle

Pebble-sized sediment

Hydraulic action

Where the force of water breaks up rocks by infiltrating cracks, through the direct impact of the water or through the compression of air

Abrasion

Where a wave picks up sediment and throws these load items against a rock; the repeated impact chips away at the rock face until small fragments break away

Corrosion

Where acidic water in waves dissolves rock minerals, which are carried away in solution

Attrition

Where material transported by a wave is eroded through collision with other load items

Wave cut notches

A curved indentation of about 1-2 m high extending along the base of a cliff

Wave cut platform

A flat rock surface exposed at low tide, extending out to sea from the base of a cliff.

Cliffs

Steep slopes that are usually unvegetated

Traction

Where large, heavy load items are rolled along the sea bed

Saltation

Where lighter sediment bounces along the sea bed

Suspension

Where very light sediment is carried aloft within a body of water or air

Solution

Where sediment is carried dissolved within the water

Longshore drift

The net lateral transport of material along the coastline when waves approach the coast at an angle

Current

The flow of water in a particular direction

Tides

The flow of water in a particular direction, and they can transport sediment in the nearshore and offshore zone

Prevailing wind

Most common wind direction

Dominant wind

Strongest wind direction

Tidal range

The distance between high tide and low tide

Beaches

Accumulations of sand and/or shingle found in the foreshore and backshore zones

Bayhead beaches

Curved beaches found at the back of a bay

Spits

Linear ridges of sand or shingle beach stretching into the sea beyond a turn in the coastline but connected to the land at one end

Hooked/recurved spit

A spit whose end is curved landwards, into a bay or inlet

Double spit

Where two spits extend out in opposite directions from both sides of the bay, towards the middle

Offshore/breakpoint bars

Ridges of sand or shingle running parallel to the coast in an offshore zone

Bars/barrier beach

Linear ridges of sand/shingle extending across a bay and are connected to land on both sides

Tombolos

Linear ridges of sand and shingle connecting an offshore island to the coastline of the mainland

Cuspate foreland

Low lying triangular shaped headlands, extending out from a shoreline, formed from deposited sediment when longshore drift currents from opposing directions converge

Sediment cell/Littoral cell

A linked system of sources, transfers and sinks of sediment along a section of coastline

Inputs/sources

Places where sediment is generated

Transfers

Places where sediment is moving alongshore through longshore drift and offshore currents

Outputs/sinks

Locations where the dominant process is deposition and depositional landforms are created

Physical/mechanical weathering

The application of force to physically fragment rock into smaller pieces called clasts

Freeze-thaw weathering

When water seeps into cracks in rocks & freezes, expanding in volume by 9% and fracturing rock

Salt crystal growth

When repeated tidal cycles lead to salt crystal growth in rock cracks, exerting tensional pressure

Wetting & drying

When rocks containing clay minerals are soaked with sea water & expand, then dry & shrink; repetition of this eventually causes rock to fragment & crumble

Chemical weathering

Where chemical reactions attack individual minerals in the rock, breaking bonds and producing new chemical compounds

Carbonation

When carbonic acid rain mixes with calcium carbonate in rocks to dissolve the minerals

Hydrolysis

The breakdown of minerals to form new clay minerals, plus materials in solution, due to the effect of water and dissolved carbon dioxide

Oxidation

The addition of oxygen to minerals, especially iron compounds, which produces iron oxides and increases volume, contributing to mechanical breakdown