Download to an introductory Plate Tectonics exercise for a

PlateTectonicsExercise
Step1:
OnyourPCorlaptopgotothewebURLbelow:
http://geode.net/pangaeaBreakup/
Youshouldseethefollowingwebpage:
ClicktheupperbluebuttontodownloadthePangaeaBreakupKMLfiletousethe
animationintheGoogleEarthapplication(whichneedstobeinstalledonyour
computer).TodownloadGoogleEarthforyourcomputer,gohere:
https://www.google.com/earth/download/ge/agree.html
Onceyouhaveeverything
installedandhaveopened
thePangaeaBreakup.kml
fileinGoogleEarth,a
virtualgloberenderingof
thesupercontinentPangaea
(liketheimagetotheright)
shouldappearafterafew
minutes(thismaytake
longeronanoff-campus
computer.)
Step2:
Atthispointyoushouldseesomethingliketheimageatthebottomoftheprevious
page.ThisisavirtualglobeanimationofthesupercontinentPangaeaandits
subsequentbreakupspanningthetimeperiodfrom200Ma(millionyearsago)to
thepresent.
SpendthenextseveralminutesexploringthevariousaspectsofthePangaea
Breakupinteractiveanimation.
Thingstonote:
- OntheleftsideoftheGoogleEarthwindow,youwillseea“Places”
windowthathasthePangaeaBreakupfolderlistunderthe“Temporary
Places”folder.Youwillusetheselectionboxesforthefolderslistedunder
thePangaeaBreakupheadingtocontrolwhatisshowninthemain
GoogleEarthwindow
- Underneaththe“Places”windowyouwillseea“Layers”window.Make
suretodeselect(turnoff)the“PrimaryDatabase”,whichshouldbethe
topitemintheLayerswindow
- NowlookingatthemainGoogleEarthwindow(thatshowsthevirtual
globe),youcanrotatethevirtualglobetoanydesiredviewpointby
clickingontheglobeandmovingyourmousewhileholdingdownthe
mousebutton
- ThetimeperiodinMa(millionsofyearsago)forthecurrently-displayed
arrangementofcontinentsisshowninyellowattheupperrightofthe
screen
- Intheupperrightcornerisaverticalscalebarthatyoucandragupand
downtozoominandoutofspecificlocations
- Youcanchangethegeologictimeperiodshownbyslidingthewhitetab
onthebluebaratthetopleftcornerofthewindow
- Inthe“View”dropdownmenuatthetopofthescreenyoucantogglea
latitudeandlongitudegridbyclicking“Grid”
- Continentscanbeselectedanddeselectedviacheckboxesbyeach
continentnameinthe“Places”window
- Otherfeatures,suchasMountainBelts,HotSpots,FossilDistribution,etc.
canbeshownusingthecheckboxesinthe“Features”menu
- ExploreautomatedanimationsofthebreakupofPangaeafromvarious
viewpointsbyselectingalocationinthe“Tours”menu
OnceyouhavefamiliarizedyourselfwiththePangaeaBreakupinteractive
animation,proceedwiththeexercisethatfollows.
Name(s)
Date
PlateTectonicsExercise
Background–PlatetectonicsdescribestheEarth’scrustasbeingarigidexterior,
whichisdividedintoseveralslabs,or“plates”,whicharelocatedabovethe
convectingmantleandmovethroughtime.DissipationofheatfromtheEarth’s
interiordrivesplatemovement.Theboundariesbetweenplatescanbeconvergent
(collisional),divergent(extensional),orside-to-sidemovement(strike-slipor
transformmovement)andtypicallyfeaturemountainranges.
ThetheoryofplatetectonicswasinfluencedbyAlfredWegener’shypothesisof
continentaldrift,introducedin1915.Wegenersuggestedthattherewasoncea
singlelandmass,orsupercontinent,thathereferredtoas“Pangaea.”Someofthe
evidencethatWegenerusedincluded:theapparentjigsawfitofthecontinents,
fossilevidence,evidenceofpastglaciations,andthecorrelationofancientmountain
beltsacrosscontinents.
Wewillexplorethisevidenceforplatemovementinthisexercise.UsethePangaea
Breakupmodeltoanswerthefollowingquestions.
JigsawfitoftheContinents–ThePangaeaBreakupmodelshowsthe
movementoftectonicplatesoverthelast200millionyears.Itshows,indetail,the
movementofplatesthatWegenerproposedin1915.Exploreplatemovement/
continentaldriftbyansweringthequestionsbelow.
1.WhenPangaeawasstillasupercontinent(200Ma),whichpresent-daycontinent
waslocatedattheNorthPole(HINT:TurnonGrid)?
a. Antarctica
b. Australia
c. Eurasia
d. NorthAmerica
2.Approximatelyhowmanymillionsofyearsago(Ma)didpresent-dayIndiabreak
awayfrompresentdayMadagascar?
a. 20Ma
b. 50Ma
c. 80Ma
d. 120Ma
3.From90Matothepresent,whichcontinent/landmasstravelledthegreatest
distance(HINT:TurnonGridandestimatedegreesoflatitudeorlongitude)?
a. Africa
b. India
c. NorthAmerica
d. SouthAmerica
4.Intermsofitsgeographiclocation,whichmoderndaycontinentisclosestto
whereitwasat200Ma?
a. NorthAmerica
b. SouthAmerica
c. Antarctica
d. Australia
MountainBelts–Thecorrelationofancientmountainbeltsacrossnow
separatedcontinentswasanotherpieceofevidencethatsupportedtheideaof
continentaldrift.Select“MountainBelts”andexplorethisideabyansweringthe
questionsbelow.
5.Whichmountainbeltswereadjacenttoeachotherpriortothebreakupof
Pangaea(HINT:Zoominorclickonthegreenmountainsymbols)?
a. CascadeandMauritanian(westernAfrica)mountains
b. Ouachita(SENorthAmerica)andGreenlandmountains
c. GreenlandandCaledonian(easternEurope)mountains
d. MauritanianandSierraNevadamountains
6.Whatmountainbeltsonnow-separatedcontinentswerelikelyconnectedasa
singlemountainbeltonthesupercontinentofPangaea?
a.
b.
c.
d.
TheAndesandtheRockies
TheAlpsandtheAtlas(Africa)Mountains
TheSredinnyRange(easternAsia)andtheSierraNevadaMountains
TheAustralianAlpsandtheTransantarcticMountains
7.WhichofthefollowingexplanationsmostlikelydescribeshowtheHimalaya
Mountainsformed?
a. TheAfricanPlateandEurasianPlatecollidedtoformthemountains
b. TheIndianPlateandEurasianPlatecollidedtoformthemountains
c. ThePacificPlateandEurasianPlatecollidedtoformthemountains
d. Alargemantleplume(hotspot)locatedundertheEurasianPlateformed
aseriesofvolcanicridges
8.WhatisthebestexplanationforwhytheHimalayaMountainsarehigherin
elevationthantheAndesMountains(SouthAmerica)?
a. TheHimalayasareolder
b. TheAndeshavemorevolcanicactivity
c. TheAndesformedbecauseofanocean-continentcollision
d. TheHimalayasformedbecauseofacontinent-continentcollision
FossilEvidence–Thepresenceofthesamefossilspeciesinnowseparated
continentsisfurtherevidenceforcontinentaldrift.Select“Fossildistribution”to
explorethisideainthequestionsbelow.
9.WhichfossilsarefoundinSouthernAfrica(HINT:Zoominorclickonthefossil
symbols)?
a. Cynognathus
b. Lystrosaurus
c. Mesosaurus
d. Alloftheabove
10.Glossopterisisanancientfern-likefossilfoundonAntarctica.Whereelsecan
thisfossilbefound?
a.
b.
c.
d.
India
Australia
SouthernAfrica
Alloftheabove
11.Mesosaurusisafresh-waterreptilefossilfoundoncontinentsinthesouthern
hemisphere.Basedonthelocationsofthesefossils,whichcontinentswith
Mesosaurusfossilswerelikelyadjacenttoeachother?
a. AntarcticaandIndia
b. AfricaandSouthAmerica
c. AustraliaandIndia
d. NorthAmericaandEurope
GlacialEvidence–Paleozoicglaciationsthatcanbefoundatlocationson
severalcontinentsareevidencethatthecontinentswereonceconnected.Select
“Paleozoicglaciation”andexplorethisideabyansweringthequestionsbelow.
12.WhichmoderndaycontinentdoesnotshowevidenceofPaleozoicglaciation?
a. Australia
b. Africa
c. NorthAmerica
d. SouthAmerica
13.Glacialevidencelocatedneartheequatorsuggeststhatthosecontinentswere
oncelocatedincolderregionsnearthepoles.Whichcontinentshaveglacial
evidenceneartheequatortoday?
a. AustraliaandAntarctica
b. AfricaandSouthAmerica
c. NorthAmericaandEurasia
d. Alloftheabove
ModernPlateTectonics
PlateBoundaries–Thereare3basictypesofplateboundaries:
Convergent–Whenplatescometogether.Oneplatewillbesubductedunderthe
other.Thisformsfeaturessuchasmountains,islandarcsystems,andocean
trenches.
Divergent–Whenplatesmoveapart.Thiscreatesspreadingcentersthatshowup
asseafloorspreadingzonesinoceaniccrust,andriftvalleysincontinentalcrust.
Transform–Whenplatesslidepasteachother.Theyareverycommoninoceans
wheretheyoffsetmid-oceanridges.Theycanalsoformplateboundarieslikethe
SanAndreasFaultinCalifornia.
Select“Presentplateboundaries”andexploreplateboundariesbyansweringthe
questionsbelow.
14.WhattypeofboundaryisfoundbetweentheSouthAmericanPlateandthe
NazcaPlate?
a. Convergent
b. Divergent
c. Transform
d. Undefined
15.WhatisthemainplateboundarytypefoundattheMid-AtlanticRidge?
a. Convergent
b. Divergent
c. Transform
d. Undefined
16.Whattypeofpresent-daycollisionformedtheHimalayanMountainsatthe
boundarybetweentheIndianPlateandtheEurasianPlate?
a. Continent-continentcollision
b. Continent-oceancollision
c. Ocean-oceancollision
d. Undefined
17.Whattypeofpresent-daycollisionformedtheCaribbeanIslandsattheeastern
boundarybetweentheCaribbeanPlateandtheNorth/SouthAmericanPlates
(HINT:deselectBlueBackgroundtoseetheCaribbeanIslands)?
a. Continent-continentcollision
b. Continent-oceancollision
c. Ocean-oceancollision
d. Undefined
Hotspots–Columnsofrisingmoltenmaterialfromdeepinthemantle,knownas
“mantleplumes,”risetothesurfacewheretheenergyisreleasedvia“hotspot”
volcanoes.Whenlong-livedmantleplumesencounteroceaniccrusttheycreate
hotspotchains,duetothemovementofatectonicplateoverarelativelystationary
hotspot.AnexampleofthisistheHawaiianIslandchain.Whenmantleplumes
encountercontinentalcrusttheycreatevolcaniccalderas,suchastheYellowstone
Caldera.Select“HotSpotVolcanos”andexplorehotspotsbyansweringthe
questionsbelow.
18.Whatistheageoftheoldestseamount(DetroitSeamount)intheHawaiian
Islandchain(HINT:RunthetimesliderbackwardsuntiltheDetroitseamountisat
thelocationoftheHawaiianmantleplume)?
a. 6Ma
b. 34Ma
c. 39Ma
d. 78Ma
19.WhatistheoldestvolcanicfeatureintheYellowstoneHotspotchain?
a. YellowstoneCaldera
b. WalcottTuff
c. MesaFallsTuff
d. McDermittCaldera
20.TheNinetyEastRidgehotspots(intheIndianOcean)initiatedwiththe
Kerguelenfloodbasaltplateaus(outlinedwithredpolygons)thatincludedBroken
Ridge.WhendidtheKerguelenplateausstarttoform?
a. ~50Ma
b. ~80Ma
c. ~110Ma
d. ~140Ma
SelectedReferences
Bird,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's
oceanfloor,JournalofGeophysicalResearch,vol.102,p.3211–3214.
Müller,R.D.,Sdrolias,M.,Gaina,C.andRoest,W.R.,2008,Agespreadingratesandspreading
asymmetryoftheworld'soceancrust,Geochemistry,Geophysics,Geosystems,vol.9,Q04006,
doi:10.1029/2007GC001743.
Torsvik,T.H.,Steinberger,B.,Gurnis,M.andGaina,C.,2010,Platetectonicsandnetlithosphere
rotationoverthepast150My,EarthandPlanetaryScienceLetters,vol.291,p.106-112,doi:
10.1016/j.epsl.2009.12.055.