Coasts part 2- landforms, management and SL Flashcards
Factors affecting rate of erosion
-Waves
-Rock type/structure
-Sub-aerial processes
-Presence/absence of a beach
-Coastal management
Development
How different processes operate to change the physical characteristics of an area
Landscape
The big picture; entirety of the sea, coast and rolling countryside
Landforms
Individual components of the landscape; cliffs, wave cut platform etc.
3 ways of classifying coastlines
-Concordant and discordant
-Cliffed coast, flat coast, graded shoreline
-Emergent or submergent coastline
Discordant coastline
Rock bands alternate between hard and soft rock and are at a right angle to the coastline
Headlands and bays on a discordant coastline
Differential erosion of hard and soft rock results in bas being created where soft rock was and leaving headlands jutting out into the sea
Concordant coastline
Alternating bands of hard and soft rock that run parallel to the coastline
Headlands and bays on a concordant coastline
Waves break through a weaker crack in the hard rock and create bays as the soft rock erodes faster
What is a cliff
A mass of resistant rock
What is a wave cut platform
A gently sloping platform of rock stretching out from the cliff to the sea (with an angle of less then 5 degrees)
Formation of a cliff
Land is weathered and eroded through hydraulic action and abrasion to create a drop between the land and the sea
Formation of a wave cut platform
Waves focus erosion between the high and low tide levels through abrasion and hydraulic action. This leads to a wave cut notch growing until the cliff is completely undercut
What is a geo
A narrow, steep sided inlet or gorge typically found on hard rock cliffs
Formation of a geo
Created when a fault line is differently eroded to form a gully, though it may begin as a sea cove. Faults are enlarged by ,marine erosion through hydraulic action and abrasion
What is a blowhole
Vertical clefts or splits in coastal cliffs which link sea caves to the cliff top
Formation of a blowhole
Formed along coastlines due to hydraulic action; incoming waves trap and compress air within a cave and repeated force can puncture the roof of the cave and water and spray will be driven through the roof of the cave.
Swash aligned beaches
Sediment moves up and down the beach with little lateral transfer; this happens when the waves break parallel making curved and concave beaches.
Drift aligned beaches
Produced where waves break at an angle to the coast; swash occurs at an angle but backwash is perpendicular to the beach. Material is transferred by longshore drift.
Shingle beach profiles
Steeper as more water drains between the air bubbles between the rocks making the backwash less effective at dragging sediment down the beach. Sediment is also harder to move on a shingle beach.
Sandy beach profile
More gentle profile due to sediment being lighter and easier to move.
What is a berm
Ridge of sand indicating the high tide mark
Formation of a berm
Constructive waves push sediment up the beach and deposit it
formation of sand ripples
Formed as the tide goes out, only on sandy beaches and only visible at low tide