1.2 Coastal Processes - Marine Erosion, Transportation and Deposition

What types of waves are responsible for marine erosion along a coast?

Destructive waves

What are the four waves destructive waves cut into the coastline?

1. Hydraulic action

2. attrition

3. corrosion

4. abrasion

Define Hydraulic action

the sheer force of the waves hitting the coast

Define Abrasion

Also calles corrasion, is when waves pick up material and hurl it at the coast, creating dents and cracks in the coast

Define Attrition

• Materials (roch, shingles) that are carried by the waves

• bump against each other and are worn smaller and smoother

Define Corrosion

• Corrosion (or solution) creates the slight acidity in seawater

• this gradually dissolves types of coastal rocks (e.g. limestones)

From where do materials in the sea come from?

• eroded from cliffs

• transported by longshore drift along the coastline

• brought inland from offshore by constructive waves

• carried to the coastline by a river

By which processes is Material in the water moved?

• traction

• saltation

• suspension

• solution

Define Traction

Traction is where large heavy material is dragged along the sea floor

→ rubs against sea floor

Define Saltation

Saltation is where smaller material is bounced along the sea floor

Define Suspension

Suspension is where fine material is held in the water

Define Solution

Solution is dissolved material which is carried in the water.

Define Longshore drift (LSD)

Longshore drift is the main process if transportation along the coast

Describe and explain Longshore drift

1. waves approach beach at an angle due to the prevailing wind (usual wind direction)

2. as waves break, swash carries material up the beach at same angle

3. as swash dies away, backwash carries the material down the beach at a right angle (90°)

4. the process repeats, transporting material along the beach in a zig zag movement

Define Prevailing wind

Prevailing wind is the usual wind direction

State the different depositions of sediments on a beach

• beach berm

• shingles

• coarse sand

• fine sand

• mud

• low water mark