weathering, erosion, deposition changing earth’s surface … athering_rock2.jpg

WEATHERING, EROSION, DEPOSITION

Changing Earth’s Surface …

http://mrbova.wiki.williamsvillek12.org/file/view/weathering_rock2.jpg/289607043/weathering_rock2.jpg

http://www.ratestogo.com/blog/wp-content/uploads/2008/08/triberg-waterfalls.jpg

WEATHERING

Surface processes that work to break down rock into smaller and smaller piecesThe small pieces are called sediments which become part of the process of soil-formation.

MECHANICAL &CHEMICAL

2 Types of Weathering

Mechanical Weathering

Occurs when rocks are broken apart by physical processes The Chemical composition of the rock stays the same

(same substance—different shape or form.)

http://watermarked.cutcaster.com/cutcaster-photo-100408368-Broken-Rock.jpg

SAME

AGENTS OR CAUSES OF MECHANICAL WEATHERING

●WIND --carries sand and debris which scrapes away at rocks.

http://img.ehowcdn.com/article-new/ehow/images/a07/sf/01/type-weathering-occurs-deserts-800x800.jpg

http://noeleen.student.cdi.ul.ie/wp-content/uploads/2010/08/arizona-butte.jpg

AGENTS OR CAUSES OF MECHANICAL WEATHERING

WATER –as it flows over rocks

Big Bend– Water erosion from the

Rio Grande River

http://explore.ecb.org/videos/VLC_media?P1=VLC161&REFERER=OTHERhttp://dpsdhaligaon.files.wordpress.com/20

07/03/rocks-in-stream-1024x768.jpg

AGENTS OR CAUSES OF MECHANICAL WEATHERING

PLANTS –roots, seeds fall into cracks and sprout, breaking them apart more.

http://explore.ecb.org/videos/VLC_file?TYPE=Image&P1=1956&REFERER=OTHER#

http://img.geocaching.com/cache/d4fb66d9-ebf4-4328-b116-507cd6ecf624.jpg

AGENTS OR CAUSES OF MECHANICAL WEATHERING

●ANIMALS– burrowing or pounding of feet on rocks

http://sustainablog-org.wpengine.netdna-cdn.com/files/2011/06/goat-herd-china.jpg

Hey kid, get off the rock!

AGENTS OR CAUSES OF MECHANICAL WEATHERING

PRESSURE– force of something –other rocks falling, movement etc.-causes rock to break

http://oldstersview.files.wordpress.com/2007/12/falling-rock.jpg

http://www.scienceclarified.com/photos/fault-2840.jpg

TEMPERATURE CHANGES(hot days—rocks expand; cold nights—rocks contract and this causes rocks to crack)

AGENTS OR CAUSES OF MECHANICAL WEATHERING

http://geology.about.com/od/geoprocesses/ig/mechweathering/exfoliation.htm

http://www.msnucleus.org/membership/html/k-6/rc/rocks/3/images/rc3r05.jpg

http://www.divinetechies.com/tapl/images/ExpansionJoint.jpg

http://www.nachi.org/forum/attachments/f23/9357d1172112437-expansion-control-joints-masonry-wall-cohen-017.jpg

ICE/FROST WEDGING--

AGENTS OR CAUSES OF MECHANICAL WEATHERING

http://mail.colonial.net/~hkaiter/science%20images/frostwedging.gif

http://www.sciencephoto.com/image/118866/530wm/C0055123-Frost_wedging_or_ice-fractured_granite-SPL.jpg

http://geology2.wikispaces.com/file/view/weathering_2.jpg/273081678/weathering_2.jpg

Occurs when chemical reactions dissolve the minerals in rocks or change them into diff erent minerals.• This changes the chemical composition of the rock, which can weaken/dissolve it.

CHEMICAL WEATHERING

AGENTS OR CAUSES OF CHEMICAL WEATHERING

1. WATER—MOST IMPORTANT agent of chemical weathering. (many minerals dissolve in water; water mixes with and carries other substances)

2. OXYGEN –oxidation-oxygen reacts with something else (rust, etc.)

weakens rocks.

http://0.tqn.com/d/geology/1/0/f/X/1/peridrustedandfresh.jpg

A

AGENTS OR CAUSES OF CHEMICAL WEATHERING

3. LICHENS AND PLANT ACIDS—roots of some plants or when they decay on rocks, lichens give off acids that break down rock.

4. OTHER ACIDS— Carbonic acid –dissolves minerals in limestone—caves

(carbon dioxide + water=carbonation) -Acid rain caused by burning fossil fuels

http://cosmictusk.com/wp-content/uploads/FrioBatCave.jpg

TEXAS CAVES

http://ts4.mm.bing.net/images/thumbnail.aspx?q=4785560495326747&id=f3041ee827c29b155327a96c53494

17a

Factors that affect the rate of weathering(how fast they weather)

1. Climate –pattern of weather that occurs in a particular area over many years.*Chemical—more rapid * Mechanical –more

rapidin warm, wet (tropical) climates in cold climates (ice)

http://www.bbc.co.uk/nature/images/ic/credit/640x395/p/po/polar_region/polar_region_1.jpg

http://www.ecosystema.ru/08nature/world/43lao/18.jpg

Factors that affect the rate of weathering(how fast they weather)

2. ROCK TYPES— can also affect the rate of weathering in a particular area because some minerals dissolve easier than others

Example: limestone etc.

3. The more surface area (outside) that is exposed to weathering, the faster the rock will weather

A. B.

“B” would weather faster than “A” because more is exposed to the elements

*PROCESS THAT WEARS AWAY SURFACE AND

MOVES THEM FROM ONE PLACE TO ANOTHER

(SEDIMENTS ARE MOVED.)

EROSION

CAUSES/AGENTS OF EROSION

1. Wind (blows)

2. Water (flows)

3. Gravity (pulls)

4. Glaciers (scrape)

Click here.

http://landslides.usgs.gov/research/other/images/Image66.jpg

MASS MOVEMENT

Any type of erosion that happens as gravity moves materials downslope. Ex. landslides—rockslides, mudslides, creep, etc.

http://www.cbc.ca/gfx/images/news/photos/2008/07/30/bc-080730-rockslide-cp-FULL.jpg

http://nimg.sulekha.com/business/original700/taiwan-landslide-2010-4-27-6-49-7.jpg

TAIWAN LANDSLIDE 2010

DEPOSITION

Dropping of sediments that occurs when agents of erosion lose energy

http://www.buzzle.com/images/geography/river-delta.jpg

http://canarygeog.canaryzoo.com/Geog1/glacial%20deposition.jpg

These processes work together in a cycle that constantly changes Earth’s surface (landforms, shorelines, coastlines,

etc.)These processes also help in the formation of soil.

Weathering

Erosion

Deposition

Sediments are broken off

Carried Away

and dropped elsewhere

(when agents or erosion lose

energy)

SOIL

Mixture of weathered rock, decayed organic matter, mineral fragments, water, and air that can take thousands of years to develop.

http://142.23.40.13/courses/st11/images/soil02.jpg

SOIL EROSION

Removal or loss of soil due to wind or water.

It is harmful in 2 ways:1. Plants need soil to grow2. Eroded fertile soil causes sedimentation

in (clogs) waterways and releases agricultural pollution into surface waters

*Can happen naturally or by humans

SOIL EROSION

Soil is eroded when it is moved from where it formed and it occurs when water flows along Earth’s surface or when wind picks up and moves sediment.

Many human activities disturb the natural balance between soil formation and soil erosion.

SOIL EROSION

2 Main Categories (Human activities contributing to soil erosion)

1. ConstructionRemove vegetation, breaking up dirt, etc.

Prevention – covering the site with mulch mats, plastic, etc., wetting dirt, plastic fencing around the site.

http://www.freeholdscd.org/upload/20080114150024_4500_FSCD-SoilErosion.jpg

SOIL EROSION

o 2. Farming – ▪ Plowing soil, animals overgrazing, removing crops

over and over again.• Prevention—Alternating crops, shelter belts of

trees, terracing on sloped fields which makes shorter slopes, no-till farming.

http://www.forestry.ok.gov/Websites/forestry/Images/windbreaks.JPG

Shelter belts of trees Terracing

NO-TILL FARMING

STRIP CROPPING

CLICK THIS PICTURE FOR VIDEO : The Basics: Earth's Changing Surface

The Basics: Earth's Changing Surface