ocr a level coasts

system

a group of objects and the relationship between them

geomorphic processes

processes resulting in the formation and shaping of lanforms and landscapes

open systems

a type of system whose boundaries are open to both inputs and outputs of energy and matter

input

the addition of energy or materials to a system

output

the transfer of energy and/or materials out of a system

deposition

the laying down of sediment transported by rivers, waves, glaciers and wind, as energy levels decline

weathering

the in situ breakdown of rocks at, or near, the land surface by physical, chemical and biological processes.

mass movement

the downslope transportation of material under gravity.

erosion

the wearing away and/or removal of rock and other material by a moving force.

stores

the parts of a system in which material and/or energy accumulates.

longshore drift

the movement of sediment by waves and currents along a coastline.

equilibrium

a long-term balance between inputs and outputs in a system.

negative feedback

an automatic response to change in a system that restores equilibrium.

sediment cell

a stretch of coastline and its associated nearshore area within which the movement of coarse sediment, sand and shingle is largely self-contained.

closed system

a system with inputs and outputs of energy, but wiothout any movement of materials across system boundaries.

fetch

the distance of open water in one direction from a coastline, over which the wind can blow.

aeolian processes

erosional, transportational and depositional processes by the wind

wave period

the time period between successive wave crests arriving at a given point

storm waves

a wave generated locally by high wind energy

crest

the highest point of a wave

trough

the lowest point of a wave

wave height

the vertical distance between trough and crest

wavelength

horizontal distance between the crests or between the troughs of two adjacent waves

swash

the movement of water up a beach after a wave has broken

backwash

flow of water down a beach after a wave has broken

constructive waves

waves in which the swash is more powerful than the backwash

destrictive waves

waves in which the backwash is more powerful than the swash

breaker zone

near shore area where waves first begin to break

swash zone

the part of the beach dominated by swash and backwash

tide

the periodic rise and fall of the sea level under the gravitational pull of the moon and sun

tidal range

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

geology

the study of the earth, specifically rocks and the planet's crust

lithology

the chemical and physical characteristics of rock types

structure

the physical characteristics of rocks, including their jointing, bedding, faulting, angle of dip etc.

discordant

a coastline with bands of different geologies lying perpendicular to the coastline

concordant

a coastline with bands of different geologies lying parallel to the coastline

ocean currents

the large scale horizontal flow of ocean water (at the surface and at depth) driven by planetary winds and contrasts in water temperature and salinity.

sub-aerial processes

a collective term for weathering and mass movement processes

sediment budget

the balance of sediment volume entering and exiting a particular section of the coast

Physical weathering

disintegration of rocks by physical forces, like pressure release, ice wedging, freezing and thawing, exfoliation

freeze-thaw

a mechanical weathering process caused by water, confined in rock joints, expanding as it freezes, and as a result breaking rocks into smaller particles

pressure release

the disintegration of rocks caused by a release of pressure by the removal of overlying mass.

thermal expansion

increase in volume of water due to its rise in temperature

salt crystallisation

a mechanical weathering process whereby formation of salt crystals leads to disintegration of rocks

chemical weathering

decomposition of rocks by chemical processes leading to the creation of new chemical componds.

oxidation

a chemical process that weathers certain types of rock and involves the absorption of oxygen from either the atmosphere or water by rock minerals

carbonation

a chemical weathering process whereby carbon

solution

the chemical weathering process by which rock minerals are dissolved

hydrolysis

A chemical reaction that leads to decomposition of rocks by the addition of water.

hydration

the breakdown of rocks by cycles of wetting (expansion) and drying (contraction)

biological weathering

the breakdown of rocks through the chemical and physical action of living organisms e.g. burrowing, tree roots etc.

root action

the biological weathering process by which rock is broken apart as roots grow and expand

burrowing

the biological weathering process caused by animals digging.

chelation

a type of chemical weathering caused by acids derived from rainwater and organic material

rockfall

a mass movement process affecting steep slopes over 70 degrees in angle

slide

a mass movement process where cohesive material moves downslope along a straight slip plane.

slump

a mass movement process where material moves downslope along a curved slip plane

abrasion

an erosion process whereby material being transported rubs against surfaces leading to smoothed surfaces

attrition

the erosion of sediment transported by rivers, glaciers, waves and winds leading to smaller rounder particles

hydraulic action

the erosion process by which water forces air into cracks in the rock leading to disintegration

corrosion

The decomposition of rock due to a chemical reaction with water

traction

the transport process by which large material is rolled along the river or sea bed.

saltation

the transport process by which material is hopped or bounced along the bed

suspension

the transport process by which fine material is carried by the energy of the water

solution transport

the transport process by which minerals are dissolved and carried by the water

marine processes

processes operating upon a coastline that are connected with the sea, such as waves, tides and longshore drift.

fluvial processes

processes involving the work of running water on the surface of Earth

flocculation

a process by which salt causes the aggregation (clumping) of minute clay particles into larger masses that are too heavy to remain suspended in water

erosional landforms

the category of landforms shaped predominantly by erosion processes

cliffs

rugged steep or vertical landforms found on coastlines.

shore platforms

A smooth erosional surface that develop in the surf zone adjacent to coast lines.

bay

an inlet along a coastline, usually between two headlands

headland

a promontory extending out from the coastline

wave refraction

the process by which waves slow down and wave crests bend towards due to the uneven shallowing of water.

blowholes

Formed when a joint between a cave and the land surface becomes enlarged and air can pass through it

geos

a narrow, steep sided inlet

cave

an erosional landform usually found in a headland between low water mark and high water mark

arch

an erosional landform formed when a cave is eroded through the headland.

stack

a tall erosional landform formed by the collapse of an arch

stump

a short erosional landform formed after the partial collapse of a stack

depositional landforms

the category of landforms shaped predominantly by deposition

beach

A depositional landform comprising of an accumulation of sediment on the shoreline

spring tide

The tide with the greatest tidal range (the highest high tide and the lowest low tide)

neap tide

The tide with the smallest tidal range (the lowest high tide and the highest low tide)

intertidal range

The vertical distance between high tide and low tide

wave energy

a measure of the kinetic energy carried by waves

beach profile

a cross section of beach, measured with a clinometer, tape-measure and ranging poles

beach angle

a measure of how steep or shallow a beach is

spit

a depositional landform occuring after a sharp change in the direction of the coastline. Formed by longshore drift transporting sediment and depositing it as a finger protruding out into the sea.

salt marsh

a depositional landform often forming in the lee of a spit where deposited sediment is innundated twice daily by tides. This creates a halosere which is populated by halophytic species

onshore bar

formed when a spit extends across a whole bay and rejoins the land forming a lagoon behind it

tombolo

a beach which joins the mainland to an offshore island

turbid

cloudy or muddy conditions owing to sediments held in suspension

delta

a large area of sediment found at the mouth of a river.

cuspate delta

a pointed extension to the coastline caused by sediment accumulation which is shaped by regular, gentle currents from opposite directions

arcuate delta

a delta in which there is sufficient sediment supply for the delta to grow seawards, but wave action is strong enough to smooth and trim its leading edge.

birds foot delta

a delta in which distributaries build out from the coast in a braiding pattern, with river sediment supply exceeding the rates of removal by waves and currents.

Are tides predictable?

Yes because it happens at regular intervals.
Two high and two low tides are experienced at coastal places on Earth every 24 hours.

What are the two types of currents?

Surface ocean currents (wind) and deep ocean currents (temperature/salinity)

igneous rock

a type of rock that forms from the cooling of molten rock at or below the surface