Theme B Flashcards
Coastlines are ‘dynamic’. What does that mean?
Dynamic means they can change over time due to wave action(Constructive and destructive waves)
What are the two types of waves?
Constructive and destructive
What is Swash?
Swash is the water going towards the beach
What is Backwash?
Water going to back to the sea
Differentiate Constructive and Destructive Waves
Constructive add sediment to the shore and form beaches, Destructive destroy beaches
What is a Fetch
Distance of water over which the wind blows
Factors which affect the strength of waves
Fetch
Strength of wind
Wind blowing for longer time makes bigger waves
Explain attrition
Rocks colling with rocks forming smaller rocks
Explain abrasion/corrasion
Rocks rubbing against sea bed
Explain Hydraulic action
Force of water wearing away the rock
Explain Solution/Corrosion
chemical action of rocks dissolving
Explain Constructive waves
Low and far apart
6-9 per minute
common in summer
Strong swash
weak backswash
Explain Destructive Waves
High and close together
15 per minute
Common in Winter
String backwash
weak swash
Explain Suspension
small fragments of rocks carried along the flow of water
Explain Traction
large rocks rolling across river bed
Explain Saltation
Large fragments of rocks bouncing across sea bed
Explain Solution
Dissolved Particles Carried across the water
Explain Longshore Drift
Longshore drift is the** zigzag movement of material along the shore** . It happens when waves approach the beach at an angle due to the angle of the prevailing winds.
The swash carries material up and along the beach in an angle. The backwash carries material back down the beach at right angles. This is the result of gravity.
Explain the Formation of Headlands and Bays
When coastlines has areas of harder and softer rock, the soft rock will wear away, leaving hard rock sticking out to the sea. This makes a Headland
Explain Wave Cut Platform
Caused when EROSIONAL PROCESSEs OF HYDRAULIC ACTION AND ABRASION erodes a Rocky Headland and creates a WAVE CUT NOTCH.
Overtime the notch get bigger and undercuts the rock forming a overhang and collapses forming a cliff. This process is repeated to create a flat exposed area at the base of the cliff called a Wave Cut Platform. The process repeats
Explain CCASS
Large crack is opened up by hydraulic action along the weaker part of the rock from wave action
The Crack grows into a cave by hydraulic action and abrasion
Cave becomes larger and breaks through the headland and forms an arch
When the roof of the arch collapses in leaves a stack, which can be eroded to leave only a stump
Explain Sandy Beach
swash=Backwash
Sediment is spread across
Flat
Explain Shingle Beaches
Swash>Backwash
Sediment piles up at the top of the beach
Steep
Explain Spit
Spit is an extended beach that forms a finger of land sticking out into the sea. It is formed when sediment is carried along by longshore drift and deposited out into the sea where the coastline turns a corner
