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Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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Presentation on theme: "Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit."— Presentation transcript:

1 Wind and Wave Erosion

2 How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

3 What is Loess and how does it form? It can be 1m to 100m deep. Made of mineral & rock particles. It is wind-carried sediment & when dropped, it will hold together so well that when it erodes, it splits off vertically to form cliff-like slopes. Main deposits of loess in the U.S. include Mississippi & Missouri river valleys.

4 What is a sand dune? Sand dunes - hills of sand deposited by wind. They form when the sand piles up against shrubs, boulders, or other substances.

5 How does a Sand Dune Migrate? When wind blows against the windward side (side facing into the wind) of a dune, some of the surface sand is carried over top & falls on the leeward side (side facing against the wind)

6 Types of Sand dunes 1. Barchans – crescent-shaped & the ends of a barchan point downwind.

7 Types of Sand dunes 2. Transverse – Where sand is more abundant, long continuous sand ridges form at right angles to the wind. Found on beaches.

8 Types of Sand dunes 3. Parabolic – (u-shaped) dunes often form around blowouts. Unlike barchans, the open ends of parabolic dunes face upwind. Found on beaches.

9 Types of Sand dunes 4. Longitudinal – Form in desert regions with lots of sand. These dunes are long, straight ridges that are parallel to the general wind direction.

10 Draw a wave and label its parts (Crest, Trough, Height)

11 How do swash and backwash work together? Swash - the motion of water up the beach. Backwash – the motion of water running back down the beach

12 What is a longshore current? How does it affect someone swimming at the beach? It runs parallel to shore. It moves people down the beach.

13 What is a rip current? Why is it dangerous? Strong surface currents that flow away from the beach. They can reach up to 5 km/hr. & carry you away from shore.

14 Describe the process of a sea cliff turning into a sea stack. (4 parts) 1. Sea cliff - waves cut out rock & make a notch

15 2. Sea cave - notch will deepen & make a hole

16 3. Sea arch – waves cut through walls of sea caves to make an arch

17 4. Sea stacks – roof of sea arch falls into water

18 What is a sandbar? A sandbar is a bar of sand formed by ocean currents depositing sand near the shore underwater

19 What is a spit? A sandbar attached at one end to the shoreline.

20 What is a hook? A spit with a curved end

21 What is a barrier island? Barrier islands are sandbars not attached to land or the shoreline and are above water

22 What is a tombolo? A tombolo is a bar of sand that joins an island to the mainland.

23 What is a bay mouth bar? A bay mouth bar is a spit that completely closes access to a bay, thus sealing it off from the main body of water.


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