Flashcards in 3.3 - Coastal geomorphology processes Deck (41)
Process at base of atmosphere which breaks down the coastline and weaken the underlying rock so a sudden movement of erosion can happen easily
What is a marine process?
Operate upon a coastline and are connected with the sea (LSD, tides)
Long short drift - prevailing winds at an angle to the coastline and swash transports sediment up the beach then backwash transports it towards sea at a right angle.
What is an offshore current?
E.g. rip current - move material to sea at a right angle. Sediment is deposited t form a sand bank or reshape depositional landforms
Movement of cooler water from deep ocean due to surface winds pushing water away.
What is a longshore current
Approach coast at an angle and generate a current running parallel to the shore. Transports sediment and water
3 causes of a current
Wind, water temperature, salinity
Large movement of water in one direction
What is a rip current
Formed when a series of plunging waves cause a temporary build up at the top of a beach. Met will resistance from breaking waves. Backwash is forced below surface.
Wall of water that travels upstream for a considerable distance
What is solution (transportation)
Dissolved material that is not visibly moving
What is suspension
Small particles oved by light currents
What is saltation
Pebbles bounce of sea bed
What is traction
Rocks are dragged/rolled on sea bed
4 reasons why energy flow declines and description
Energy source changes - weaken currents/prevailing winds
Discontinuity in flow - turbulence between opposite currents (end of spit)
Increased friction - more energy needed to big rocks deposited
Increased load - energy of system isn't sufficient (sudden river discharge or landslip)
What is the different between corrasion and abrasion
Corrasion - throw at cliff
Abrasion - drag along floor (sand paper)
How does the wave steepness impact the rate of erosion?
Wave steepness - high energy = longer fetch = high and steep
What are aeolian processes
Entrainment, transport and deposition of sediment by wind
3 types of weathering
Biological, chemical, physical/mechanical
What is biological weathering?
Action of vegetation and organisms. E.g. seaweed and plant roots
2 examples and processes of mechanical weathering
Freeze thaw = +- 0oc. Water enters crack, freeze and expand up to 10%, exert pressure and crack widens (pressure relief)
Salt crystallisation - sea water enters crack, freeze and expand, evaporate and salt left behind, repeat
Name the 5 types of chemical weathering
Define mass movement
Downslope movement of material due to gravity
Blocks dislodged by weathering fall
Block of rock rapidly move along seaward dipping plane
Define rotational slump
Sections of cliff give way on concave surface and rock/soil s unconsolidated
Storm/intense rainfall - soil lying over impermeable bedrock
Slow downslope movement of individual soil particles
Slow downslope of waterlogged regrowth. End of ice age (thaw)