Ordinary Waves are caused by wind


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  • Ordinary Waves are caused by WIND

    • Waves are produced when wind drag causes the surface water of oceans/lakes to rise and fall
    • - Waves get refracted on approaching shoreline




Ocean waves originate in stormy, windy areas. When they meet they add and subtract, so that the swell is organized into sets of waves, wave trains, of different wavelengths, speeds and amplitudes

  • Ocean waves originate in stormy, windy areas. When they meet they add and subtract, so that the swell is organized into sets of waves, wave trains, of different wavelengths, speeds and amplitudes

  • Period is the time it takes two crests to pass

  • P = f (wavelength, speed)

  • Amplitude is wave height

  • Long period, low amplitude waves last longer





Wind energy transferred to water surface

  • Wind energy transferred to water surface

  • Efficient orbital motion cycles energy KE <=> PE

  • Considered “deep” until depth < 1/2 λ









The origin of hooks has many theories

  • The origin of hooks has many theories

  • Ocean wave refraction from opposite shore of Baymouth

  • Onshore storm surge from Hurricanes

  • Strong onshore winds hurricanes & Nor'easters

  • Tidal: High tide carries sediment into bay, deposits new sediment at higher elevations. Low tide water level lower; ebb flow re-suspends only the portion deposited in deep water: high deposits safe













Strong onshore winds build parabolic dunes along the shore, bedload sand moves short distances via saltation

  • Strong onshore winds build parabolic dunes along the shore, bedload sand moves short distances via saltation

  • Grains above high tide



shaped by non-marine processes, by changes in the land form.

  • shaped by non-marine processes, by changes in the land form.

  • in much the same condition as it was when sea level was stabilized after the last ice age

  • Primary coasts are created by erosion, deposition, or tectonic activity

  • were formed as the sea level rose during the last 18,000 years, submerging river and glacial valleys to form bays and fjords.

  • An example of a primary coast is a river delta, which forms when a river deposits soil and other material as it enters the sea. BUT, if the delta is swept away, a secondary coast is created.



a landform that is formed at the mouth of a river.

  • a landform that is formed at the mouth of a river.

  • flows into an ocean, sea, estuary, lake.

  • formed from the deposition of the sediment carried by the river as the flow enters the sea or lake and competence drops.



much of the sediment emanating from the river mouth is deflected along the coast line by longshore currents, forming spits, barrier bars and lagoons, etc.

  • much of the sediment emanating from the river mouth is deflected along the coast line by longshore currents, forming spits, barrier bars and lagoons, etc.

  • Deltas of this form, such as the Nile Delta, tend to have a characteristic delta shape .



Strong Tidal influence

  • Strong Tidal influence

  • Ebb and flow of tides distributes sediment offshore, much of delta is underwater

  • Distributaries become trumpet-shaped



produced by marine processes, such as the action of the sea or by creatures that live in it.

  • produced by marine processes, such as the action of the sea or by creatures that live in it.

  • Secondary coastlines include sea cliffs, barrier islands, mud flats, coral reefs, mangrove swamps and salt marshes.





A steep slope is easier to erode, a gentle slope does not erode rapidly

  • A steep slope is easier to erode, a gentle slope does not erode rapidly



Postglacial rise in sea level is complicated by rebound.

  • Postglacial rise in sea level is complicated by rebound.

  • Rise often cuts a new platform on old hillside

  • Water rises, erodes higher

  • Then rebound raises the land, surf zone cuts into lower part

  • Shear cliffs result















Return flow from longshore currents

  • Return flow from longshore currents





Ridges exposed at low tide, survive after the storm surge ends

  • Ridges exposed at low tide, survive after the storm surge ends





Based on work on pluvial Lake Bonneville by G.K.Gilbert

  • Based on work on pluvial Lake Bonneville by G.K.Gilbert







In seawater, clay flocculates into round bunches, heavier, settles in slow water

  • In seawater, clay flocculates into round bunches, heavier, settles in slow water

  • Bloom p. 439 (paraphrased): Clay along shore suspended, carried into lagoon by high tide. Lagoons are shallow, so mud can settle quickly.

  • Fraction falls and sticks in lagoon, rest carried out to ocean again, where water is deep

  • Most offshore mud bunches still suspended next incoming tide, another chance to settle out and stick to the lagoon bottom.





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