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The Work of Waves and Wind

. . wave length. wave height. . crest. . trough. particles in waves follow a circular pattern. . COASTAL LANDFORMS. At the shoreline. Water becomes shallow, wave height increases because wave length decreasesWaves become steeper, then collapse (breakers). Surf - sequence of breaking wavesSwash - water sliding up beachBackwash - water flowing back down beach to sea.

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The Work of Waves and Wind

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    1. The Work of Waves and Wind Objectives: Explain the characteristics of ocean waves and tides Present coastline features of erosion, transport and deposition Examine the processes of wind erosion and deposition Differentiate different types of dune Describe the wind deposit LOESS

    3. At the shoreline Water becomes shallow, wave height increases because wave length decreases Waves become steeper, then collapse (breakers)

    4. Surf - sequence of breaking waves Swash - water sliding up beach Backwash - water flowing back down beach to sea

    5. Wave refraction Close to coast, water gets more shallow Waves are slowed down If waves arrive at an angle, one part is slower than the rest Causes waves to bend = wave refraction

    6. Wave refraction

    7. Waves arriving at bays are slow (deposition) At headlands, faster (erosion)

    8. A sequence of features is produced as headlands are degraded Sea cliffs Waves erode base -undercutting

    11. Longshore drift Waves arrive at a coast at an angle (swash) Backwash returns at 90 degrees

    12. Coastal deposition Result of longshore drift and a lot of sediment = produces extensions of deposit from the shoreline

    13. May grow across a bay (baymouth bar) May link an island to the main land (tombolo)

    17. Types of Coastline

    18. Emergent coast Uplifted land surface Coastal landforms are found above present sea level

    19. Submergent coast Rise in sea level Submergent coast Landforms under water A ria coastline is an example of submergence

    20. Submergence Shorlines Ria coast - shorline valleys eroded by rivers are submerged has many offshore islands exposure to waves erodes islands and headlands Fiord coast - shoreline valleys created by glaciers are submerged valleys are deep and straight because of the depth, there are few beaches

    21. Barrier Island Coasts Occur on low lying coasts with gentle gradients BARRIER ISLANDS - low ridges of sand built by waves behind the islands are lagoons shallow water with tidal deposits TIDAL INLETS - gaps between the islands

    22. Delta and Volcano Coasts DELTA - deposit by rivers entering the sea Water slows down and spreads out as it enters Channel divides and subdivides to create DISTRIBUTARIES Volcano coasts develop in volcanic deposits Low cliffs form in fresh lava

    23. Coral reefs Corals build up calcium deposits to produce reefs To grow, corals need: Clear, warm, shallow water Wave action

    24. Coral reefs Fringing reef - directly attached to an island or coast Barrier reef - lagoon between coast and reef Atoll reef - circular reef surrounding a lagoon (no land in centre)

    25. AEOLIAN (Eolian) LANDSCAPES Wind erosion, transport and deposition Occurs in dry regions, with little vegetation such as deserts and coastal landscapes

    26. Wind Erosion Faster the air flows, more erosion Erodes more rapidly if wind blows constantly from one direction 2 TYPES OF WIND EROSION ABRASION and DEFLATION

    39. LOESS Finely textured sediment wind-blown long distances Wind-blown glacial debris formed large deposits

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