1 / 48

Coastal Landforms

Coastal Landforms. Basic Concepts. I. Sea level changes repeatedly 422 ft. eustatic rise since 18,000 years ago. specific landscapes submergent or emergent depending on tectonic change II. Waves and resultant currents erode, transport, and deposit sediment load. rocky headlands

slade
Download Presentation

Coastal Landforms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Coastal Landforms

  2. Basic Concepts • I. Sea level changes repeatedly • 422 ft. eustatic rise since 18,000 years ago. • specific landscapes submergent or emergent depending on tectonic change • II. Waves and resultant currents erode, transport, and deposit sediment load. • rocky headlands • beaches • III. Tides affect all coastal life but have little topographic effect. • tidal bores

  3. Eustatic Change and Submergent vs. Emergent Coastlines • during ice ages sea level sinks as ocean water compresses and more water is tied up in glaciers. • During interglacial periods sea level rises, flooding many former river valleys creating bays and estuaries. • In areas with rapid tectonic uplift emergent cliffs common and bays rare.

  4. Submergent Coastlines Sea level rise inundated many coastal valleys creating bays and estuaries. These coasts are referred to as ria coastlines. Estuary - An arm of the sea that extends inland to meet the mouth of a river.

  5. Emergent Coastlines Tectonic forces lift coastlines faster than sea-level rises. Dramatic cliffs and marine terraces tower above the sea.

  6. Coastal Erosion - dependent on wave size, angle, and frequency. Focused where waves contact coast. • Headlands, sea cliffs, bluffs, sea stacks, natural bridges • Beach Erosion • Coastal Transportation - wave action creates strong currents parallel to shore. Large waves move beach sand offshore. Small waves push it back on shore. • Longshore current • Coastal Deposition – where wave action is reduced, beaches and dunes form. • beaches • dunes • sand spits COASTAL FLUVIAL PROCESSES/LANDFORMS

  7. Isla Vista Beach, October 2001

  8. Isla Vista Beach, December 2002

  9. Beach Erosion

  10. Marine Terraces

  11. Point Reyes National Seashore

  12. Wave Refraction - waves change directional trend as they approach shore. Raglan, New Zealand

  13. Tombolo

  14. Tombolo

  15. Sand Spit

  16. Sand Spit

  17. Sand Spit

  18. Sea Stacks

  19. Natural Bridges and Arches

  20. Barrier Islands

  21. Barrier Islands

  22. Outer Banks, North Carolina

  23. Tropical Coasts

  24. Factors Correlated with Healthy Coral Reef Growth • water temperature range: 18 – 29C • normal seawater salinity: 32 – 35 ‰ • clear, transparent water • little or no sedimentation • vigorous water motion

  25. Tropical Mangroves

  26. Mangroves create tidal forests. These rich ecosystems provide habitat for countless creatures and help to stabilize and, by catching sediment, even create coastline.

  27. Tides Tides rise and fall with the rising moon, an interval of 24 hours and 50 minutes. There is a bulge on both sides of the earth. Thus two high tides each cycle. Flood tide (low to high) takes 6:13 and then ebb tide (back to low) is another 6:13.

  28. Tides Tide range dependent on relative position of earth, moon, and sun. Spring Tides - highest tidal range Neap Tides - lowest tidal range

  29. Tides Tide range dependent on relative position of earth, moon, and sun. Spring Tides - highest tides. Neap Tides - lowest tides. Full Moon Half Moon

  30. Tides Low Tide, New Brunswick

  31. Tides

More Related