SLOW Processes that Shape the Earth Part 1. WEATHERING

Mrs. WrightHugh B. Bain Middle SchoolCranston, RI

SLOW Processes that Shape the Earth

PART 2. EROSION1Earth - developed over long periods of time through continual change processes.

STUDENTS:Evaluate slow processes of 1) weathering 2) erosion and 3) mountain building. The following slides are on erosion.Determine how the earth has changed and will continue to change over time.

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EROSION Process by which natural forces or agents (wind, water, ice, or gravity) move weathered rock and soil from one place to another Sediment Deposition Material moved by erosion (pieces of rock, soil, plant, & animal)Occurs where agents of erosion deposit sediment & changes shape of landcover0116sediment.jpg creek edge showing tiers of sediment deposition & gravelnorthcoastjournal.com

3Causes of Erosion1. Gravity2. Running Water3. Glaciers4. Waves5. Wind

4What is gravity ? Force that moves rock and other materials downhill causing mass movement1. Gravity5Types of Mass Movement Caused by GravityA. LandslidesB. MudflowsC. SlumpD. Creep

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A .a FAST Process LandslidesOccurs when rock & soil slide quickly down a steep slope Most destructive landslide.jpgIn my earlier post, we discussed the causes of landslides.kshitija.wordpress.com

7B. a FAST Process Mudflowsueol_02_img0070.jpg scienceclarified.com

Rapid downhill movement of a mixture of water, rock, & soil

8C. a FAST Process SlumpMass of rock & soil suddenly slips down a slope in one large mass (often when water soaks bottom of clay soil) slump1.jpgSlump at Double Ditch - April, 1988 (Burleigh County, N.D.) more mass ... umt.edu

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D. CreepVery slow downhill movement of rock & soil (often from freezing & thawing of water in cracked layers of rock beneath soil

creep_kathryn1.jpg shoop2010.weebly.com10Major agent of erosion that shaped Earths land surface

2. Running Water

splash_eriosion.jpgRaindropRaindrops loosen soil & carry particles.11Runoff Water that runs over the Earths surface

runoff.jpgSurface runoff absoluteastronomy.com12

Forms of Runoff (smallest to largest):Rills Gullies Streams Rivers Lake13

Running Water - Runoff Rill

rill.jpg14

Gully

runoff670291.jpgA channel with water only after it rains15

Stream

9907_05_15Stream_web.jpg Stream freefoto.com

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River

fallsrivertowardssheepfalls.jpg rivers flyfishingfrenzy.com

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Lake

Vg025.jpg large lake shannontech.com

18RiversThrough erosion, rivers can create a variety of features

fallsrivertowardssheepfalls.jpg rivers flyfishingfrenzy.com19River FeaturesA. ValleysB. WaterfallsC. Floodplains D. Meanders E. Oxbow lakes

20A. Valley Elongated low area between hills formed by a stream

258530373_87b9bf351d.jpgKullu Valley's Beas River formed ...flickr.com21B. Waterfall Occur where a river meets rock that erodes slowly & flows over softer rock downstream

waterfallLG.jpgLargest waterfall in Lesotho, Africatodayscampus.com22C. FloodplainFlat, wide area of land along river.

Lower down on its course where land slopes gently, river spreads out forming a river valleyFloodplains here

floodplain.jpg floodplain belmont.sd62.bc.ca23D. MeanderLoop-like bend in the river (S shape - Mississippi)

meander_word_picture.jpg Meandering csahf.blogspot.com24E. Oxbow LakeMeander that has been cut off from the riverHorseshoe shape

Oxbow_lake,Yamal_Peninsula,Russia.JPGdic.academic.ruagilogy.com25Oxbow LakeDuring a flood, high water finds a straighter pass downstreamAs water falls, sediments dam up ends of meander

ForminganOxbow111232009.jpgOxbow Lakes Kentucky, United States ...geocaching.com26What are glaciers? Any large mass of ice that moves slowly over land 3. Glaciers27Types of GlaciersA. Continental Glaciers B. Valley Glaciers28A. Continental Glacier Covers much of a continent Flow in all directions as they move (like pancake batter in frying pan)In distant past covered one third of Earths landHave advanced, then retreated (last time - 10,000 yrs ago), or melted back, several times

ContinentalIce.jpg The Continental Ice Sheet is the most significant of all the glacial agents ... homepage.montana.edu29B. Valley GlacierLong & narrow glacierForms when snow & ice build up high in a mountain valley

Sides of mountain keep them from spreading out in all directionsUsually move down valleys already cut by riversMuch smaller than continental glaciers

TidewaterGlacier.jpg There are an estimated 100000 valley glaciers travelwithachallenge.com30Processes of Glacial ErosionA. PluckingB. Abrasion31A. PluckingGlacier picks up rocks as it flows over land;

Rock fragments & boulders freeze to glacier bottom & are carried.

030515_75mhadaidh.jpgPLUCKING a type of erosion. geogars.wordpress.com32B. AbrasionMany rocks remain on bottom & get dragged alongGouges & scratches bedrock

striations.jpgAbrasion sometimes results in striations (scratches on the bedrock)geogars.wordpress.com33Landforms from Glacial DepositionA. TillB. MoraineC. Kettle

34A. Till Mixture of sediments (sand, silt, clay, boulders) deposited directly on surface

till2.gifArea adjacent to Sherman glacier is covered with a coarse glacial till.pubs.usgs.gov35B. MoraineTill deposited at edges of glacier form ridge (Long Island, NY)

03riverthumb608x456.jpgMuch of New York's Long Island was once the ...blogs.nationalgeographic.com36C. KettleDepression formed when ice is left in glacial till

When ice melts, kettle remains forming ponds or kettle lakes

kettle1.gif The largest kettle shown is ~ 150 feet in diameter. Bering Glacier flows ... pubs.usgs.gov37Form from wind that blows across waters surface

Shape coast through erosion by breaking down rock & transporting sand & other sediment.4. Waves38Landforms Created by Wave ErosionA. HeadlandB. Sea ArchC. Sea CaveD. Sea Stack E. Wave Cut Cliff

39A. HeadlandPart of shore sticks out into ocean

Made of hard rock that resists erosion longer

headland_soldiers_rock.jpgHeadland right of Soldier's Rockislaygallery.com40B. Sea Arch

seaarchvolcanoesnational.jpgSea arch - Volcanoes National Parktripadvisor.com070906045.jpgIlena in her kayak going through a sea arch(cave) on ...bryanhansel.com

the_other_way.1212007260.seaarch.jpgSea arch, Tutukaka, New Zealand. Poor Knights Islandstravelpod.com

41C. Sea Cave

FolgaSkerry.jpgSea Caveslandforms.eu Sea+Cave.jpgJust one of many sea caves seen on the trip.kauai-artist.blogspot.com

SandIslandSeaCaves.jpgMadeline Island Sea Caves. Top Canoe destination in the world, ... en.petitchef.com

42D. Sea Stack

Climbers_on_the_450ft_Sea_Stack_Old_Man_Of_Hoy,_Orkney.jpgClimbers on the 450ft sea stack Old Man Of Hoy, Orkney heason.netIMG_3180.jpg Sea Stacks ideaphore.org

43E. Wave Cut Cliff

calif_wavecutcliff.jpg wave cut cliff www2.pvc.maricopa.edu44Deposits by WavesA. BeachB. Longshore DriftC. SandbarD. Barrier Beach45A. Beach

EastBeach2.JPGEast Beach ...riparks.com46B. Long Shore DriftWaves repeatedly hit beach, beach sediment moves down beach with currentspit beach that projects out like a finger result of longshore process

CapeFear.jpg longshore drift.geolab.unc.edudungenessspit.jpgDungeness Spit, Straight of Juan de Fucalivingwilderness.com47C. Sand Bar

Long ridges of sand parallel to shoreAustralia_Lakeland_Island_Sand_Bar.jpg735 450-Lakeland Island Sand Baraustraliaadventures.com48D. Barrier Beach Form when storm waves pile up large amounts of sand forming long, narrow island parallel to coast

14.jpgGravel barrier beach, Coombs Cove, Hermitage Peninsula.gsc.nrcan.gc.ca49Wave TermsA. ImpactB. Abrasion

50A. Impact Large waves hit rocks with force & break apart rocks

stockphotosmallwaveimpactstone55974676.jpgsmall wave impact stoneshutterstock.com51B. Abrasion Wave in shallow water picks up sediment that hits land where it wears away at rock

coast.jpgAbrasionWave Pounding sixthsense.osfc.ac.uk525. Wind53Wind causes erosion by:A. DeflationB. Abrasion

54A. Deflation Process where wind removes surface materials

deflation_sm.jpgdeflationbelmont.sd62.bc.ca55B. Abrasion May polish rocks but causes little erosion

rock_wind_abrasion_p0772932441_NRCS.jpgFigure 20.4 Rock sculpted by wind, Utah. Courtesy NRCSuwsp.edu56Deposition Forms:A. Sand DunesB. Loess Deposits

57A. Sand Dunes

egyptsanddunes300632ga.jpgPhoto: Sand dunes ...photography.nationalgeographic.com58B. Loess Deposits Very fine sediment made up of silt & clay so it travels far

D015060.jpgLoess Depositsfacweb.bhc.edu59Looking at the SLOW process of erosion just discussed, how has the earth changed over time?

Is it still changing? How do you know? Give at least three examples.

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