topic: wind erosion - t-birds earth...

Topic: Wind Erosion

A. Mainly in arid (dry) regions – little vegetation

B. Carries only small sediments

Wind erosion mainly occurs:

Which way was the wind blowing?

• Ventifact – rock abraded by wind-driven sand

• Approaching dust storm at Prowers County,

CO. Storm lasted from 4:15 PM to 7:00 PM.

"Fleeing a dust storm". Farmer Arthur Coble and sons walking in the face of a dust storm, Cimmaron County, Oklahoma. Arthur Rothstein, photographer, April, 1936. (Library of Congress)

Iraq, 2005

Dune Formation

http://highered.mcgraw-

hill.com/sites/0072402466/student_view0/chapter

13/animations_and_movies.html#

http://dli.taftcollege.edu/streams/Geography/Animations/CrossBedding.html

Types of Dunes

1. Barchan

2. Transverse

3. Linear

4. Parabolic

Parabolic Dunes, Napeague Bay

Parabolic Dunes, Napeague Bay

Parabolic Dunes, Napeague Bay

Eolian (Wind) Features

Topic: Wave Erosion

http://stevekluge.com/geoscience/images/waves2.jpg

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1604/es1

604page01.cfm?chapter_no=visualization

http://stevekluge.com/geoscience/images/waves2.jpg

Montauk Lighthouse on top of Turtle Hill, 297 feet from the tip of Montauk Point (1800)

Recent Photo 2001

Wave Erosion

Wave Erosion

Lake or Ocean waves removing sediments from the beaches.

North of Santa Cruz, California

Top View of the Beach

Ocean

Beach

Where is

my towel?

Long Shore Current

Sand

Long Shore Current

• Transports water & sediments parallel to the beach.

• Long Island’s (LI) Montauk to NY City (mainly east to west)

L.I. Natural Beach Features

1) Sand Bar

2) Spit

3) Lagoon (Great South Bay)

4) Barrier Island (Fire Island)

Diagram showing the environments of a barrier island system. (from Blatt, et al, 1980, Petrology of Sedimentary Rocks)

A sandbar off of Suffolk County, Long Island, New York, August 2006.

Fire Island, Barrier Beach

Davis Park

Democrat Point

L.I. Manmade Beach Structures

1) Jetty – keep inlets open

2) Groin – collect sand (large beach)

*BIG impact on the beach erosion rates.

Jetties

Jetty

Picture taken by Kory Gately

Groin

Beach

Long Shore Current Direction

Groin

What direction is the longshore current moving?

What direction is the longshore current moving?

Coastal Erosion

• http://www.youtube.com/watch?v=zUh3W

eilFN4

Final Question

What do you predict will happen to the

houses below?

Shape of Particles Vs. Form of Erosion

Shape of the Sediments

A. Water Erosion Produces rounded

particle Stream or beach

erosion (smooth and rounded)

B. Wind Erosion Produces rounded particles or particles

flattened on one side.

Appears rounded and frosted.

C. Glaciers Produces partly rounded and scratched

particles

A) Where bedrock is relatively soft, glacial grooves can be very deep. Glacial grooves in Devonian dolomite in Yule Creek a little east of the Yule Colorado Quarry. Gunnison County, Colorado. (All images and portions of captions from USGS).

U- shaped valleys

U Shaped Valley found in Greenland

D) Gravity and Physical Weathering

Produces angular particles