Oceans and Coasts & Shorelines	


low tide to high tide
Active Margins - coincide with a plate boundary
Passive Margins - do not coincide with a plate margin
great quantities of sediment are often trapped along 
shorelines


Significance of Shorelines	


approximately 67% of the Earth's population live in a narrow 
belt parallel to the coastlines.
processes taking place along a shoreline play a major role in 
determining what happens to this population.


Waves	


Waves can be created when wind moves across the surface of 
a body of water
	Fetch - the distance the wind blows - 
	The greater the fetch the greater the size of the wave


Waves can be created by any process that displaces the body 
of water - earthquakes, for example - Tsuanami


Waves

Until they are close to shore, the water molecules move up and 
down
The speed of a wave (the clerity) is the wavelength/period
	the wavelength is the distance from crest to crest or trough to 
trough
	the period is the time between adjacent crests

Wave Base


the wave base is 1/2 of the wavelength - if the wavelength is 6 
feet, the wave base if 3 feet.
when the water depth is less than the wave base, the wave is 
slowed down as it begins to interact with the bottom of the 
basin.
Wave Refraction is initiated.


Wave Refraction


Breakers form when the wave base is reached
 the waves begin to bend because part of a wave front may be 
affected by wave base whereas the other part is not .... 
a Longshore current develops which moves parallel to the 
shoreline

Tides	


The positions of the Earth, Moon and Sun control the location 
of the tides 
the effect of the moon is the dominate factor
If the Earth - Moon separation distance decreased, what 
would happen to the tides?

Environments of Accumulation


Beaches - low tide to high tide
Spits - sand bar extends into a body of water - such as Cape 
Cod, MA
Barrier Islands - parallel to the coast line - when sea level rises 
the barrier islands move inland.




Off Shore


Plate Tectonics
Spreading Centers
Deposition in Deep Water
	A continental component - delivered by turbidity currents - 
submarine canyons
	a Pelagic component - sediment suspended in the water 
column - CCCD