Coast Terms (Especially 4 Geography As)

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Term

Definition

Details

Type

Onshore

A movement from sea to land

Usually used to descibe winds

Coastal Environment

Backshore

The beach area, landward of the foreshore above the normal reach of the tides, that provides the primary protection from the hinterland

Coastal Environment

Intertidal and Nearshore

Zone of land between highest and lowest tides

In low-lying areas i.e mudflats, this can be very extensive and important ecologically

Coastal Environment

Offshore Zone

A zone that is seaward of the breakpoint

This may include features such as offshore bars

Coastal Environment

Coast

The area where landmasses meet the sea

Often used to encompass the zones on either side of the shoreline

Coastal Environment

Coastline/Shoreline

A line used in the analysis of shoreline evolution

It represents the cliff top edge on cliffed coasts, edge of hard defences where these exist, and the backshore/ hinter

Coastal Environment

Coastal Zonation

The identification of areas of coast often for planning purposes

The term may refer to zones such as offshore, onshore or to sections of the coast sharing common marine processes.

Coastal Environment

Littoral Zone

The environmental zone that exists between the highest and lowest levels of the spring tides.

Coastal Environment

Beach System

The inputs, outputs, transfers, processes and stores that interact with each other on the beach

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System

Coastal System

The inputs, outputs, transfers, processes and stores that interact with each other along the coast

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System

Littoral Cells

Offshore littoral zones within which the circulation of sediment through longshore drift and other processes, is relatively self contained.

11 such zones have been identified for England and Wales

System

Sediment Sinks

These occur when sediment movements meet and material is lost from marine circulation

They are often associated with the creation of depositional features

System

Dynamic Equilibrium

The balance between inputs and outputs in a system

It is linked to the concept of "steady state"

System

Storm Surge

A rapid rise in sea level brought about by a combination of factors.

These factors include; - High sring tides - strong onshore winds - funneling of water into narrow coastal zones - very low atmospheric pressure - esturine rivers at flood level due to prolonged rainfall.

System

Storm Event

An exceptionally powerful storm with associated geomorphological consequences i.e the creation of a new storm beach

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System

Structure

Geological features

i.e folding and faulting

Physical Factor AC

Lithology

Rock Type

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Physical Factor AC

Differential Erosion

The erosion of different geological elements at different rates due to variations.

i.e lithology or faulting which may lead to features such as headlands and bays.

Physical Factor AC

Fault Zone

Area of rocks with a high degree of faulting, making it prone to erosion

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Physical Factor AC

Jointing

Fractures in rocks that do not involve faulting

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Physical Factor AC

Bedding Plane

Surface within a rock that is parallel to the surface of deposition

Often associated with cracks that may lead to erosion

Physical Factor AC

Concordant Features

Features that occur where geological structures run parallel with the coast

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Physical Factor AC

Discordant Features

Features which occur when structures run at right angles to the coast

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Physical Factor AC

Wave Frequency

The number of waves per minute

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Physical Factor AC

Fetch

The distance that a wave travels before breaking

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Physical Factors AC

Dominant Wind

The wind direction that has the principal impact on marine processes in an area

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Physical Factor AC

Prevailing Wind

The wand that blows most frequently in an area

It is often the dominant wind

Physical Factor AC

Corrasion

Erosion caused by pebbles and rock fragments hitting the beach or cliff rocks.

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C Process

Abrasion

Another term for corrasion

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C Process

Corrosion

Erosion brought about by chemical action on rocks

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C Process

Hydraulic Action

Erosion brought about by the pressure of water on cliffs and beaches.

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C Process

Wave Refraction

The "bending" of a wave due to friction as its base touches the seabed

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C Process

Longshore Drift

The movement of material along a beach caused by waves (swash) striking the beach at an angle, and the backwash returning at right angles

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C Process

Rip Currents

Fast flowing backwash that can scour beach channels

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C Process

Tides

The periodic rises and falls of sea level due to the gravitational action of the sun and moon

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C Process

Micro-Tidal Environment

The zone of littoral affected by tidal action

It has particular relevance to ecological systems

C Process

Swash

Water moving up a beach after a wave has broken

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C Process

Backwash

The movement of water back down a beach due to gravity

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C Process

Sub-aerial Erosion

Non-marine erosional processes that occur on cliff and beach surfaces

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C Process

Rotational Slipping

Landslipping that occurs on a curved plane

It is often caused by weak underlying rocks giving way during saturation

C Process

Slumping

Movement of material down a slope, under gravity, but lubricated by water

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C Process

Flow

The movement of liquid or semi-liquid material downslope e.g on a cliff face

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C Process

Landslide

Movement of dry material downslope (due to gravity) with no lubrication

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C Process

Long Term Changes

Long Term - permanent changes that occur quickly or slowly

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C Process

Short Term Changes

Changes that happen relatively quickly and usually regarded as temporary

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C Process

Active Cliffs

Cliffs undergoing active erosion

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C Landforms

Degraded Cliffs

Non-active cliffs

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C Landforms

Wave-cut notch

An "undercut" or notch at the base of a cliff caused by marine erosion

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C Landforms

Wave-cut flatform

A gently sloping platform (less than 4o) at the base of the cliff, cut by marine action

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C Landfrorms

Cliff Profile

The verticle outline or cross-section of a cliff

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C Landforms

Sea Cave

Hollow cut in a cliff by marine action

eg. limestone caves Llantwit Major

C Landforms

Sea Arch

Arch in a cliff cut by marine action

eg. Durdle Door, Dorset

C Landform

Stack

Tall remnant of a cliff, left isolated by marine action

eg. The Needles

C Landform

Stump

Short remnant of a cliff, left isolated by marine action

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C Landform

Geo

Steep sided inlet cut by marine action

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C Landform

Beach

The deposit of non-cohesive material on the interface between dry land and the sea

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C Landform

Beach Cusps

Small "embayments" found on beaches that channel swash to their centres, thus maintaining their form

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C Landform

Beach Profile

Vertical cross section of a beach

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C Landform

Storm Beach

A line of coarse material deposited on the upper beach during a storm

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C Landform

Berm

Ridge of coarse material on the upper beach deposited by spring tides and storms

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C Landforms

Spit

Long strip of shingle joined to the coast

This results from marine deposition

C Landforms

Bar

Offshore deposit of sand or shingle

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C Landform

Tombolo

Island linked to mainland by a depositional feature such as a spit

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C Landform

Sea Level Changes

Can be positive, negative, eustatic, isostatic

Positive (a sea level rise relative to the land), Negative ( a sea level fall relative to the land), Eustatic ( changes caused by sea volume changes ie. global warming), Isostatic (changes brought about by vertical land movements ie. melting of glaciers)

C Landform

Raised Beach

Old becah left "high and dry" by falling sea level

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C Landform

Fjord

Glacial valley drowned by sea level rise to form narrow, steep sided inlet

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C Landform

Ria

Steep sided river valley drowned by sea level rise

e.g Dartmouth