coastal processes Flashcards
(17 cards)
Erosion
5
-Hydraulic action
-Wave quarrying
-Abrasion/corrosion
-Attrition
-Solution/ Corrosion
Hydraulic
- Can exert enormous pressure upon a rock surface
-The impact water has on rocks
Wave quarrying
-Breaking waves trap air, creating pressure on cliff faces, which weakens them over time
-Steep seabeds generate higher, steeper waves, and headland focus waves
Abrasion/ Corrasion
Materials like sand, shingles, + boulders carved by the sea wear away rock faces
Attrition
Rocks erode one another
Solution/ Corrosion
-PH changes cause acidic changes
- undsolves the dissolving of calcium carbonate, basalt, rocks, and limestone
The rate of coastal erosion is affected by…
- Human activity
-Fetch
-Coastal configuration
-Beach pressure
-Geology
Human activity affects coastal erosion
-Sea defence in one place can lead to an increased rate of erosion elsewhere in the same coastline.
-May reduce erosion because of sea defences
-People may remove protetive matifral from beaches (sand + shingles_—> which can lead to more erosion
Fetch affects coastal erosion
-How far the wave has travelled
-Determines how much energy has been generated
Coastal configuration affects coastal erosion
Headlands attract wave energy through refraction
Beach pressure affects coastal erosion
-Beaches absorb wave energy and can therefore provide protection against marine erosion
-Steep, narrow beaches easily dissipate the energy from flatter waves while flatter, wider beaches spread out the incoming wave energy and are best at dissipating high and rapid inputs
Geology affects coastal erosion
Rock type that is less likely to erode and be permeable
Concordant coastlines
The southern part of the coast has the rocks running parallel to it. Here, the resistant Portland limestone forms the cliffs, which have protected the coastline from erosion
Discordant coastlines
To the east, the rocks run at a right angle to the coast, allowing the sea to penetrate the weaker clays and gravels and produce large bays.
Rock dip
The steepest cliffs tend to form in rocks that have horizontal strata which dip gently inland, whereas rocks that dip towards the coast tend to produce much more gentle features
Structure of the rock
-Effect erosion
When rocks lie parallel to the coast, they produce a very different type of coastline than when they lie at a right angle to the coast
Lithology
-Especially resistant to erosion and permeability
-Very resistant rocks such as granite
-Variation in the rate at which rocks wear away is known a differential erosion
