Shorelines are places where bodies of water meet dry land


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Shorelines are places where bodies of water meet dry land

  • Shorelines are places where bodies of water meet dry land

  • Coasts are landward of ocean shorelines

  • Beach: a narrow strip of land, washed by waves or tides .

  • 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










  • Longshore current is produced as water flows parallel to coastline

  • Rip Currents are produced when water piles up in surf zones and flows seaward, generally perpendicular to the coast.







Daily rise/fall of surfaces of oceans/lakes due to gravitational pull of the Moon/Sun on the Earth– also due to force created as Earth spins on its axis

  • Daily rise/fall of surfaces of oceans/lakes due to gravitational pull of the Moon/Sun on the Earth– also due to force created as Earth spins on its axis

  • Flood tides- elevate sea surface that cause shoreline to move inland

  • Ebb Tides- low sea surface that cause shoreline to move seaward







Bay of Fundy tides reach16 m (about 53 ft) at the head of the bay. The 12.4 hour period of the twice daily lunar tides is close to the natural back and forth sloshing period of the bay.

  • Bay of Fundy tides reach16 m (about 53 ft) at the head of the bay. The 12.4 hour period of the twice daily lunar tides is close to the natural back and forth sloshing period of the bay.









Wave erosion occurs when deep water waves hit the shore with full force

  • Wave erosion occurs when deep water waves hit the shore with full force

  • Air and water are forced into cracks at high pressure











Headlands- cliffs that jut seaward

  • Headlands- cliffs that jut seaward

  • Wave-cut bench is produced when waves undercut headland

  • Sea Caves are produced when waves are refracted against the side of headland

  • Sea Arch forms when two Sea Caves erode completely through the headland

  • Sea Stack is formed when Sea Arches collapse













Riprap/Seawall- protect shore lines

  • Riprap/Seawall- protect shore lines

  • Groin – stabilizes beaches

  • Jetty – keep inlets clear

  • Breakwater – protect a harbor



















Longshore Drift causes deposits:

    • Longshore Drift causes deposits:
  • Spit is a finger-like ridge of sand deposited where Longshore drift encounters deeper water

  • Hook is a curved spit

  • Baymouth is a spit that covers the access to a bay – the area behind it fills with sediment











1. Glaciers

  • 1. Glaciers

  • Glaciers lower sea-level slowly

  • They melt quickly – sea level rises

  • 2. Mid Ocean Ridges (MOR’s)

  • Mid Ocean Ridge raises sea level if large

  • and active

  • Lowers sea level if activity slows - becomes smaller

    • Sit in the bath tub – water level rises


Coast types formed mainly from non-marine processes such as glaciation (Long Island) , stream deposition (deltas) , fluctuating sea levels

  • Coast types formed mainly from non-marine processes such as glaciation (Long Island) , stream deposition (deltas) , fluctuating sea levels

  • Also Organic Coasts - reefs, mangroves



Tectonic uplift and sea-level changes

  • Tectonic uplift and sea-level changes

  • Postglacial Isostatic rebound and sea-level changes

  • Mid-ocean Ridge grows/wanes and sea-level changes





    • Fringing Reef- initially surround land, grow seaward
    • Barrier Reef- separated from coast by a lagoon
    • Atoll- circular structure from great depth that encloses shallow lagoon
    • Mangroves










Ongoing marine erosion and deposition

  • Ongoing marine erosion and deposition

  • Erosion: Headlands, wave cut terraces, sea caves, stacks, and arches

  • Deposition: Beaches, spits, hooks, tombolos

  • Barrier Islands are nearly continuous ridges of sand parallel to main coast







Divergent/Convergent plate boundaries possess steep continental shelves

  • Divergent/Convergent plate boundaries possess steep continental shelves

  • Passive Continental Margins- have broad continental shelves and have beaches with spit

  • Island Arcs can protect coastlines

      • Allows deltas to form










Break waters, groins, and jetties all cause deposition of sediment somewhere

  • Break waters, groins, and jetties all cause deposition of sediment somewhere

  • Other areas lose beach sand

  • Development destroys vital shoreline vegetation

  • Water and petroleum pumping cause subsidence















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