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

Date post: 11-Jan-2016
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Wind and Wave Erosion
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Page 1: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

Wind and Wave Erosion

Page 2: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

How is wind abrasive?

• It carries sand grains that grind and scour anything that they hit.

Page 3: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 4: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 5: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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)

Page 6: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

Types of Sand dunes• 1. Barchans – crescent-shaped & the ends of a

barchan point downwind.

Page 7: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 8: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 9: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 10: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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

Page 11: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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

Page 12: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 13: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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.

Page 14: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

Describe the process of a sea cliff turning into a sea stack. (4 parts)

• 1. Sea cliff - waves cut out rock & make a notch

Page 15: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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

Page 16: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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

Page 17: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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

Page 18: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

What is a sandbar?

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

Page 19: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

What is a spit?

• A sandbar attached at one end to the shoreline.

Page 20: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

What is a hook?

• A spit with a curved end

Page 21: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

What is a barrier island?

• Barrier islands are sandbars not attached to land or the shoreline and are above water

Page 22: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

What is a tombolo?

• A tombolo is a bar of sand that joins an island to the mainland.

Page 23: Wind and Wave Erosion. How is wind abrasive? It carries sand grains that grind and scour anything that they hit.

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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