Download pdf - Plate Tectonics Exercise · (collisional), divergent (extensional), or side-to-side movement (strike-slip or transform movement) and typically feature mountain ranges. The theory

PlateTectonicsExercise Step1:OnyourPCorlaptopgotothewebURLbelow:

http://geode.net/pangaeaBreakup/

Youshouldseethefollowingwebpage:

ClicktheupperbluebuttontodownloadthePangaeaBreakupKMLfiletousetheanimationintheGoogleEarthapplication(whichneedstobeinstalledonyourcomputer).TodownloadGoogleEarthforyourcomputer,gohere:https://www.google.com/earth/download/ge/agree.htmlOnceyouhaveeverythinginstalledandhaveopenedthePangaeaBreakup.kmlfileinGoogleEarth,avirtualgloberenderingofthesupercontinentPangaea(liketheimagetotheright)shouldappearafterafewminutes(thismaytakelongeronanoff-campuscomputer.)

Step2:Atthispointyoushouldseesomethingliketheimageatthebottomofthepreviouspage.ThisisavirtualglobeanimationofthesupercontinentPangaeaanditssubsequentbreakupspanningthetimeperiodfrom200Ma(millionyearsago)tothepresent.SpendthenextseveralminutesexploringthevariousaspectsofthePangaeaBreakupinteractiveanimation.

Thingstonote:- OntheleftsideoftheGoogleEarthwindow,youwillseea“Places”

windowthathasthePangaeaBreakupfolderlistunderthe“TemporaryPlaces”folder.YouwillusetheselectionboxesforthefolderslistedunderthePangaeaBreakupheadingtocontrolwhatisshowninthemainGoogleEarthwindow

- Underneaththe“Places”windowyouwillseea“Layers”window.Makesuretodeselect(turnoff)the“PrimaryDatabase”,whichshouldbethetopitemintheLayerswindow

- NowlookingatthemainGoogleEarthwindow(thatshowsthevirtualglobe),youcanrotatethevirtualglobetoanydesiredviewpointbyclickingontheglobeandmovingyourmousewhileholdingdownthemousebutton

- ThetimeperiodinMa(millionsofyearsago)forthecurrently-displayedarrangementofcontinentsisshowninyellowattheupperrightofthescreen

- Intheupperrightcornerisaverticalscalebarthatyoucandragupanddowntozoominandoutofspecificlocations

- Youcanchangethegeologictimeperiodshownbyslidingthewhitetabonthebluebaratthetopleftcornerofthewindow

- Inthe“View”dropdownmenuatthetopofthescreenyoucantogglealatitudeandlongitudegridbyclicking“Grid”

- Continentscanbeselectedanddeselectedviacheckboxesbyeachcontinentnameinthe“Places”window

- Otherfeatures,suchasMountainBelts,HotSpots,FossilDistribution,etc.canbeshownusingthecheckboxesinthe“Features”menu

- ExploreautomatedanimationsofthebreakupofPangaeafromvariousviewpointsbyselectingalocationinthe“Tours”menu

OnceyouhavefamiliarizedyourselfwiththePangaeaBreakupinteractiveanimation,proceedwiththeexercisethatfollows.

Name(s) Date

PlateTectonicsExercise

Background–PlatetectonicsdescribestheEarth’scrustasbeingarigidexterior,whichisdividedintoseveralslabs,or“plates”,whicharelocatedabovetheconvectingmantleandmovethroughtime.DissipationofheatfromtheEarth’sinteriordrivesplatemovement.Theboundariesbetweenplatescanbeconvergent(collisional),divergent(extensional),orside-to-sidemovement(strike-sliportransformmovement)andtypicallyfeaturemountainranges.ThetheoryofplatetectonicswasinfluencedbyAlfredWegener’shypothesisofcontinentaldrift,introducedin1915.Wegenersuggestedthattherewasonceasinglelandmass,orsupercontinent,thathereferredtoas“Pangaea.”SomeoftheevidencethatWegenerusedincluded:theapparentjigsawfitofthecontinents,fossilevidence,evidenceofpastglaciations,andthecorrelationofancientmountainbeltsacrosscontinents.Wewillexplorethisevidenceforplatemovementinthisexercise.UsethePangaeaBreakupmodeltoanswerthefollowingquestions.JigsawfitoftheContinents–ThePangaeaBreakupmodelshowsthemovementoftectonicplatesoverthelast200millionyears.Itshows,indetail,themovementofplatesthatWegenerproposedin1915.Exploreplatemovement/continentaldriftbyansweringthequestionsbelow.1.WhenPangaeawasstillasupercontinent(200Ma),whichpresent-daycontinentwaspartiallylocatedattheNorthPole(HINT:TurnonGrid)?

a. Antarcticab. Australiac. Eurasiad. NorthAmerica

2.Approximatelyhowmanymillionsofyearsago(Ma)didpresent-dayIndiabreakawayfrompresentdayMadagascar?

a. 20Mab. 50Mac. 80Mad. 120Ma

3.From90Matothepresent,whichcontinent/landmasstravelledthegreatestdistance(HINT:TurnonGridandestimatedegreesoflatitudeorlongitude)?

a. Africab. Indiac. NorthAmericad. SouthAmerica

4.Intermsofitsgeographiclocation,whichmoderndaycontinentisclosesttowhereitwasat200Ma?

a. NorthAmericab. SouthAmericac. Antarcticad. Australia

MountainBelts–Thecorrelationofancientmountainbeltsacrossnowseparatedcontinentswasanotherpieceofevidencethatsupportedtheideaofcontinentaldrift.Select“MountainBelts”andexplorethisideabyansweringthequestionsbelow.5.WhichmountainbeltswereadjacenttoeachotherpriortothebreakupofPangaea(HINT:Zoominorclickonthegreenmountainsymbols)?

a. CascadeandMauritanian(westernAfrica)mountainsb. Ouachita(SENorthAmerica)andGreenlandmountainsc. GreenlandandCaledonian(westernEurope)mountainsd. MauritanianandSierraNevadamountains

6.Whatmountainbeltsonnow-separatedcontinentswerelikelyconnectedasasinglemountainbeltonthesupercontinentofPangaea?

a. TheAndesandtheRockiesb. TheAlpsandtheAtlas(Africa)Mountainsc. TheSredinnyRange(easternAsia)andtheSierraNevadaMountainsd. TheAustralianAlpsandtheTransantarcticMountains

7.AsectionoftheSouthernAppalachianMountainsarelocatedinVirginia(Select“Virginia”).WhichmountainbeltwasnexttotheVirginiaAppalachiansat200Ma?

a. TheAtlasMountainsb. TheCaledonianMountainsc. TheGreenlandMountainsd. TheMauritanianMountains

FossilEvidence–Thepresenceofthesamefossilspeciesinnowseparatedcontinentsisfurtherevidenceforcontinentaldrift.Select“Fossildistribution”toexplorethisideainthequestionsbelow.8.WhichfossilsarefoundinSouthernAfrica(HINT:Zoominorclickonthefossilsymbols)?

a. Cynognathusb. Lystrosaurusc. Mesosaurusd. Alloftheabove

9.Glossopterisisanancientfern-likefossilfoundonAntarctica.Whereelsecanthisfossilbefound?

a. Indiab. Australiac. SouthernAfricad. Alloftheabove

10.Mesosaurusisafresh-waterreptilefossilfoundoncontinentsinthesouthernhemisphere.Basedonthelocationsofthesefossils,whichcontinentswithMesosaurusfossilswerelikelyadjacenttoeachother?

a. AntarcticaandIndiab. AfricaandSouthAmericac. AustraliaandIndiad. NorthAmericaandEurope

GlacialEvidence–Paleozoicglaciationsthatcanbefoundatlocationsonseveralcontinentsareevidencethatthecontinentswereonceconnected.Select“Paleozoicglaciation”andexplorethisideabyansweringthequestionsbelow.11.WhichmoderndaycontinentdoesnotshowevidenceofPaleozoicglaciation?

a. Australiab. Africac. NorthAmericad. SouthAmerica

12.Glacialevidencelocatedneartheequatortodaysuggeststhatthosecontinentswereoncelocatedincolderregionsnearthepoles.Whichcontinentshaveglacialevidenceneartheequatortoday?

a. AustraliaandAntarcticab. AfricaandSouthAmericac. NorthAmericaandEurasiad. Alloftheabove

ModernPlateTectonicsPlateBoundaries–Thereare3basictypesofplateboundaries:Convergent–Whenplatescometogether.Oneplatewillbesubductedundertheother.Thisformsfeaturessuchasmountains,islandarcsystems,andoceantrenches.Divergent–Whenplatesmoveapart.Thiscreatesspreadingcentersthatshowupasseafloorspreadingzonesinoceaniccrust,andriftvalleysincontinentalcrust.Transform–Whenplatesslidepasteachother.Theyareverycommoninoceanswheretheyoffsetmid-oceanridges.TheycanalsoformplateboundariesliketheSanAndreasFaultinCalifornia.Select“Presentplateboundaries”andexploreplateboundariesbyansweringthequestionsbelow.Makesurethetimesliderissettothepresentday(0Ma).13.WhattypeofboundaryisfoundbetweentheSouthAmericanPlateandtheNazcaPlate?

a. Convergentb. Divergentc. Transformd. Undefined

14.WhatisthemainplateboundarytypefoundattheMid-AtlanticRidge?

a. Convergentb. Divergentc. Transformd. Undefined

15.Whattypeofpresent-daycollisionformedtheHimalayanMountainsattheboundarybetweentheIndianPlateandtheEurasianPlate?

a. Continent-continentcollisionb. Continent-oceancollisionc. Ocean-oceancollisiond. Undefined

16.Whattypeofpresent-daycollisionformedtheCaribbeanIslandsalongtheeasternboundaryoftheCaribbeanPlateandtheNorth/SouthAmericanPlates(HINT:deselectBlueBackgroundtoseetheCaribbeanIslands)?

a. Continent-continentcollisionb. Continent-oceancollisionc. Ocean-oceancollisiond. Undefined

17.Whereistheoldestoceancrust(oceanlithosphere)located(HINT:Select“Oceanlithosphereage”andlookforthepurplecoloredbands)?

a. ArcticOceanb. IndianOceanc. SouthernAtlanticOcean(belowtheequator)d. WesternPacificOcean(neartheAntimeridian)

Hotspots–Columnsofrisingmoltenmaterialfromdeepinthemantle,knownas“mantleplumes,”risetothesurfacewheretheenergyisreleasedvia“hotspot”volcanoes.Whenlong-livedmantleplumesencounteroceaniccrusttheycreatehotspotchains,duetothemovementofatectonicplateoverarelativelystationaryhotspot.AnexampleofthisistheHawaiianIslandchain.Whenmantleplumesencountercontinentalcrusttheycreatevolcaniccalderas,suchastheYellowstoneCaldera.Select“HotSpotVolcanos”andexplorehotspotsbyansweringthequestionsbelow.18.Whatistheageoftheoldestseamount(DetroitSeamount)intheHawaiianIslandchain(HINT:RunthetimesliderbackwardsuntiltheDetroitseamountisatthelocationoftheHawaiianmantleplume)?

a. 6Mab. 34Mac. 39Mad. 78Ma

19.WhatistheoldestvolcanicfeatureintheYellowstoneHotspotchain?

a. YellowstoneCalderab. WalcottTuffc. MesaFallsTuffd. McDermittCaldera

20.TheNinetyEastRidgehotspots(intheIndianOcean)initiatedwiththeKerguelenfloodbasaltplateaus(outlinedwithredpolygons)thateventuallyincludedBrokenRidge.WhendidthefirstKerguelenplateausstarttoform?

a. ~50Mab. ~80Mac. ~110Mad. ~140Ma

SelectedReferencesBird,P.,2003,Anupdateddigitalmodelofplateboundaries,Geochemistry,Geophysics,Geosystems,vol.4,1027,doi:10.1029/2001GC000252.Müller,R.D.,Roest,W.R.,Royer,J.-Y.,Gahagan,L.M.,Sclater,J.G.,1997,Digitalisochronsoftheworld'soceanfloor,JournalofGeophysicalResearch,vol.102,p.3211–3214.Müller,R.D.,Sdrolias,M.,Gaina,C.andRoest,W.R.,2008,Agespreadingratesandspreadingasymmetryoftheworld'soceancrust,Geochemistry,Geophysics,Geosystems,vol.9,Q04006,doi:10.1029/2007GC001743.Torsvik,T.H.,Steinberger,B.,Gurnis,M.andGaina,C.,2010,Platetectonicsandnetlithosphererotationoverthepast150My,EarthandPlanetaryScienceLetters,vol.291,p.106-112,doi:10.1016/j.epsl.2009.12.055.