1. Coastal Processes ~ erosion, transport & deposition
12.1 CA NC

2. Erosion

3. Erosional processes
Abrasion = continuous tumbling reduces rock to sand grains
Solution = salt dissolves some of the rock
Scouring = wave swirls at base of cliff & loosens rock

4. Erosion Erosional processes in action

5. Erosional Features
Sea cliff
Sea cave
Sea arch
Sea stack
Terrace

6. Sea cliff Navassa Island, Caribbean Sea
Forms when waves erode rock

7. Sea cave Short Sands Beach, Oregon
Hole eroded at base of cliff

8. Sea arch Hawaii Sea cuts through headland

9. Sea stack County Mayo, Ireland
Isolated column of rock

10. Sea terraces Haiti Flat platforms at water height

11. Features

12. Transport
Material eroded by the sea is moved along the beaches.

13. Longshore drift Longshore drift illustration
Waves approach beach at angle
Sand moves in zig zag motion
Creates longshore current
Current keeps sand moving until it hits a change or structure, then it drops out.

14. Longshore drift diagram

17. Deposition
Sand deposits form where amount of rock moving toward shore is greater than amount moving away.

20. Depositional Features
Beach
Lagoon
Tombolo
Barrier island

21. Beach Emerald Isle, NC

22. Lagoon
Vegetation is red; water is blue (satellite image)

23. Tombolo
Bar that extends out into ocean, but remains connected to mainland.
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web.macam.ac.il

24. Barrier Island

25. Barrier Islands Occur on east coast of USA
Isolated dunes become islands
Parallel to shore
Associated features:
Sound (also called bay or lagoon)
Tidal inlets
Tidal flats
Estuaries

26. HUMAN EFFECTS ON COASTLINES

31. Homework
Read pages

32. Output
Draw a block diagram of the east coast and include the features of the beaches.
Draw a block diagram of the west coast and include the features of the beaches.