Coastal Processes (Unit 2, Topic 1) Flashcards
What is a Carbon Pump?
The negative correlation between the temperature of the water and the amount of Co2 that can be dissolved
What is Volcanic Outgassing?
Releases both water and carbon into the atmosphere
What is Thermohaline Circulation?
Movement of ocean currents of heat energy and organic matter around the globe and allows carbon to be diffused into the water
What is an Example of Water Ocean Feedback Loop?
Global temperatures rise so increased oceanic temperatures so more water less able to dissolve into the ocean and is instead released leading to more Co2 in the atmosphere so global temperatures rise
What are Upwellings?
The movement of cold water from deep in the ocean towards the surface. The more dense cold water replaces the warmer surface water and creates nutrient rich ocean currents
What are Ocean Currents?
The permanent or seasonal movement of surface water in the seas and oceans. Wind drives the currents that are at a near to or at surface level. Measuring currents allows for safe docking and navigation by predicting current movement.
What are Tidal Currents?
Tides also create tidal currents that change in a regular pattern. A rise in sea level by the moons gravitational pull. This rise in water level is accompanied by a horizontal movement of water called the tidal current. Measuring currents are important to shipping, commercial fishing, recreational boating and ocean safety.
What are Longshore Currents?
Longshore currents occur when waves hit a coastline parallel at an angle, generating a flow of water parallel to the coastline, this transports sediment parallel to the coastline.
What are Rip Currents?
They are strong currents moving underwater away from the shoreline, they develop when seawater is piled up along the coastline. Initially they run parallel to the coastline before flowing out through a breaker zone. These are extremely hazardous to swimmers and small boats
How do Tides Work?
The periodic rise and fall in sea level is caused by the gravitational pull of the sun and moon. Tides create ocean currents that influence the scale and direction of coastal sediment movement, they can be used to generate renewable energy. When the moon and sun are in a straight line the tide raising force is the strongest and this occurs twice in a lunar month, these are called spring tides.
Equally twice a month when the sun and moon are perpendicular they create the lowest tidal range or neap tides. The pattern of tides are created by the Coriolis effect, morphology of the seabed and proximity of land masses. When the moon pulls there is a high tide, when the sun pulls there is a low tide
What are High-Energy Coasts?
A coastline where strong, steady, prevailing winds create high energy waves and the rate of erosion is greater than the rate of deposition
What are Low-Energy Coasts?
A coastline where wave energy is low and the rate of deposition often exceeds the rate of erosion of sediment
What are the Affecting Factors of Geology?
-Lithology
-Structure
-Dip
What are the 3 Rock Types?
Igneous rock is crystalline, resistant and impermeable (Granite)
Sedimentary rock is permeable and has air in spaces making them porous (Shale)
Metamorphic rock is very hard, impermeable and resistant (Marble)
What is Coastal Recession?
The retreat of the coastline due to erosion, sea level rise or resurgence
What are Joints?
A brittle fracture in a rocks surface where water can enter
What is Strata?
Layers of sedimentary rock that are formed through deposition, slowly changed by pressure, heat and chemical corrosion
What is Coastal Morphology?
The shape and form of the coastline influenced by rock type and structure
What are Bedding Planes?
Where layers of rock are on top of another with a line separating different rock layers
What are Folds?
Geological feature created by the deformation of rock due to comprehensive stress
What are Faults?
A fracture or zone of fractures between two blocks of rock
What is a Concordant Coastline?
Rock types run parallel to the sea, coves form here
What is a Discordant Coastline?
Rock types run at a right angle to the coast with headlands, stacks and stumps forming here
What is Igneous Rock?
Composed of two or more minerals its a volcanic rock that is roughly 2-5mm big, it doesn’t react to acids. There are two types Intrusive formed in magma and extrusive formed in lava (E.g. Basalt and Granite)
What is Metamorphic Rock
Changes from Igneous and Sedimentary rock by heat pressure, its highly resistant to erosion being dense and crystalline. It has a high melting point (E.g. Marble and Slate)
What is Sedimentary Rock?
Relatively soft and grainy, its formed in layers through consolidated deposits. Potentially containing fossils known for having oil or gas reserves (E.g. Sandstone and Limestone)
What is Abrasion/ Corrosion?
Rocks transported by waves smash and grind against other rocks or cliffs breaking bits off or smoothing them
What is Hydraulic Action?
Air in cracks are compressed when water crashes in. The pressure exerted by the compressed air breaks off rock pieces
What is Cavitation?
As waves recede, the compressed air expands violently, again exerting pressure on the rocks breaking pieces off
What is Wave Quarrying?
The energy of the wave that breaks into the cliff is enough to break bits off
What is Attrition?
Bits of rock in the water smash against each other and break into smaller pieces
What is Solution?
Soluble rocks get gradually dissolved by the seawater
What Factors Affect the Rate of Erosion?
-Beach Width
-Human Engineering
-Type of Wave
-Rock Type
-Coastal Shape
-Sea Level Rise
-Amount of Cumulated Deposition
-Wave Frequency
-Prevailing Wind
What are the Processes of Sediment Movement?
Suspension- Sediment is small enough to float in the water
Solution- Sediment has dissolved into the water (salt)
Traction- Rolls along the sea floor with wave/current energy
Saltation- Bounces along the sea floor with wave/current energy
What is Marine Deposition?
Where deposition occurs naturally and the sea loses energy and drops the sediment on a beach or ocean floor
What is Aeolian Deposition?
Wind picks up sediment from beaches and transports it downwind of the beach or further
What is Geomorphological?
The study of the Earth’s changing surface
What are the 5 Types of Geomorphological Processes that Occur at the Coast?
-Erosion
-Weathering
-Deposition
-Transportation
-Mass Movement
What is Weathering?
When rocks are broken down by chemical and mechanical processes, caused by the weather
What is Mass Movement?
When rocks are loosened by weathering moving down slope under the influence of gravity
What are the Three Types of Weathering?
Chemical- Carbonic acid from industrial pollution combining with rain creates acid rain that erodes the face of the rocks
Biological- Animals/Plants burrow into rocks creating larger cracks before breaking the rock in two
Mechanical- Freeze thaw where water freezes inside rock cracks, expands and loosens the rock before melting this repeats until the rock splits
What are Rockfalls?
Large and small fragments of rock are continually weathered and eroded until they separate and fall from the cliffs as whole parts
What are Mudflows?
Mudflows occur on very steep slopes along the coastline where there is limited vegetation and the ground is saturated. The soil continues to saturate and eventually lubricates flowing over the cliff face
What are Landslides?
The material slips down the slope and landslides more often occur on soft coastlines where water can access cracks more easier. They occur on steep slopes on concave, shallower slopes
What is Rotational Slumping?
Slumping is a large area of land moving down a curved slope plane. This usually occurs on clay cliffs that become saturated during heavy rainfall, then ooze towards the sea as a mud/ debris flow
What is Soil Creep?
This is the slowest type of downhill soil movement. Gravity pulls the water contained in soil downward, pulls the soil with it. This may give the slope a rippled effect
