Coastal Landforms
Deltas, tidal mud flats, estuaries, beaches, rocky coasts, marshes, and mangroves.
What is Coastal Landforms?
Sediment Budget: Rivers, backshore cliff, continental shelf, up-current shoreline, biological input
What is Coastal Sediment Budget Input?
Mouth bar
Prodelta (foreset)
Predelta (bottomset)
What is a Delta Front?
_______ _______ are primarily driven by friction drag between wind and ocean surface
Affected by distribution of continents, Coriolis effect, and gravity
What are "Surface Currents?"
seawater moves downward
Low biological productivity
What is Convergence Downwelling?
Passive vs active margins
A. Tectonic setting
b. Climate Zone
C. Coastal Landforms
D. Sediment Input
What is Tectonic Setting?
Sediment Budget: Waves, and wind to backshore, longshore current, offshore current
What is Coastal Sediment Budget Output
Mouth-Bar
Prodelta
Predelta
What are the parts of a Delta?
Related to the spinning of the Earth
In the northern hemisphere, flying/flowing path of an object will be deflected to the right.
In the southern hemisphere, flying/flowing path of an object will be deflected to the left.
Boundary currents
Equatorial currents
Subpolar gyres
Antarctica circumpolar current
What is the Coriolis Effect?
deeper seawater (cooler, nutrientrich) replaces surface water
High biological productivity
What is Divergence Upwelling
High, middle, and low altitudes,
A. Coastal Landforms
B. Tectonic Setting
C. Climate Zone
D. Sediment Input
What is Climate Zone?
The output is larger than the input
Bedrock exposure
Occurs commonly in coasts with steep continental shelves in tectonically active margins
What are Rocky Coasts?
Ria
Glacial age: formation of deep river valley by river downcutting Interglacial age: rising sea level floods and drowns the valley
The estuary will be filled up
Fjörd
Glacial age: formation of deep valley by outflowing glacier Interglacial age: rising sea level floods and drowns the glacial valley Very deep
What is the Formation of an Estuary?
Temperature
Mixed layer: the warmest uppermost 10-200 m.
Thermocline: the next layer where temperature drops rapidly
Deep water: the cold deep water with relatively stable temperature that does not change much with depth
Salinity
Salinity profile generally mimics temperature profiles with the highest salinity at the surface and the lowest salinity at the deep water
Halocline, a zone of rapid change in salinity
Density of Sea Water
Density increases as T decreases, and as salinity increases
T variability is much larger than salinity variability in most areas
What is Stratification of Sea Water
describes the net transport of seawater due to wind
Net transport direction at 90° right/left from the wind in the northern/southern hemisphere
What is Ekman transport?
Rivers, glaciers, waves, and winds all contain this type of sediment.
What is Clastic Sediment?
Form when a stream enters a standing water body
Current slows and loses competence
Sediment drops out
Sediment input from rivers is large enough to compensate for sediment losses due to combined wave and tidal actions
What is a Delta?
Beach Zone
Dune: sandy ridge(s) build by wind
Berm(s): the highest part of a beach built by waves
Backshore: landward sloping area behind the berm
_______: seaward sloping area fronting the berm
Nearshore: between low tide and fair-weather wave base, contains longshore trough and bars
Offshore: water deeper than the fair-weather wave base
What is Foreshore?
Ocean Circulation
_____ Ocean Currents = Upper 100s meters
What is Surface Ocean Currents?
Continental Margin
are primarily driven by friction drag between wind and ocean surface
Affected by distribution of continents, Coriolis effect, and gravity
Abyssal Plain
What is the Ocean Basin?
Waves and tides are considered ________ when it comes to Coastal Landforms
What is Transport?
Distributary channels and their floodplain (topset)
Salt marsh, Bay
What is a Delta Plain (Delta Top)?
A _________ _______ is a linear accumulation of sand that is completed separately from mainland.
Can be formed by breaching a _____ spit by storms, or by emergence of subaqueous sand bars, or by rising sea level
What is a "Barrier Island," and "Barrier?"
Deep Ocean Currents
Three major deep ocean currents:
Hint; (NADW) (AAIW) (AABW)
North Atlantic Deep Water (NADW)
Antarctic Intermediate Water (AAIW)
Antarctic Bottom Water (AABW)
Continental Shelf: <200 m deep, gently sloping
Continental Slope: relatively steep slope in front of the shelf, may be cut by submarine canyon
Continental Rise (passive margin): relatively steep slope in front of the shelf, may be cut by submarine canyon
Trench (active margin): may be filled with sediments
What is the Continental Margin?