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Captain’sTryouts2017
DynamicPlanet–Key
Writtenby:AraneeshPratap(ChattahoocheeHighSchool)
Instructionsforgrading
• For1-20:Asingleletterisgivenasthecorrectanswer.1pointeach
• For21-30:Multiplepossibleanswersforeachquestion.1/2pointeachfora)everylettercircled
onboththeteam’sanswersheetandthekey,andb)everyletternotcircledonboththeanswer
sheetandthekey.Eachquestionhasfourchoices,sothemaxscoreperquestionis2points.
• For31-50:Maximum1point.Canearnpartialcreditforsomeless-specificanswers(see
question)
• For51-57:asampleanswerisgiven,alongwiththingsthatmustbewrittentogainpoints.
• Thesectiontotalsincludelocationstoaddupbothearnedandmissedpoints,whichcanbe
checkedtoensurethattheyadduptothetotalpossiblepointsasanothermeasuretoprevent
gradingmistakes.
• Tiebreakers(inorder):11,24,33,41,45,52,54,57(i.e.checkquestion11forbothteams,if
thatdoesn’tbreakthetiethenmoveontoquestion24,etc.)
• MaximumScore:83points
SOCT2017DynamicPlanetChattahoochee–Key1
1. D̠
16. D̠
2. B̠
17. C̠
3. D̠
18. C̠
4. B̠
19. D̠
5. C̠
20. B̠
6. D̠
21. ABCD
7. D̠
22. ABCD
8. D̠
23. ABCD
9. A̠
24. ABCD
10. A̠
25. ABCD
11. D̠
26. ABCD
12. C̠
27. ABCD
13. B̠
28. ABCD
14. A̠
29. ABCD
15. D̠
30. ABCD
Total:15̠
Total:25
31. IntermontaneBasinorValley(1point)̠
32. Theoceanicplate(1point)̠
33. Noneofthem(1point)̠
34. Lithosphere(1point)̠
35. Asthenosphere(1point)(1/2pointifjust“mantle”)̠
36. OceanicCrust(1point)̠
37. ContinentalCrust(1point)̠
SOCT2017DynamicPlanetChattahoochee–Key2
38. StratovolcanoorFelsicvolcano(1point)(1/2pointifjust“volcano”)̠
39. MélangeorAccretionarywedge(1point)̠
40. Serpentinization(1point)̠
41. EclogitemetamorphismorEclogite(1point)̠
42. TheWilsonCycle(1point)̠
43. B(1point)̠
44. DandE(1pointifboth,1/2pointeach)̠
45. Peneplain(1point)(1/2pointifjust“plain.”Nopointsfor“coastalplain”)̠
46. Craton(1point),(1/2pointfor“continent”)̠
47. Clockwise(1point)̠
48. West(1point)̠
49. North(1point)̠
50. SouthAmerica(1point)̠
Total:20
51. Cordilleransubductionoccurswhenanoceanicplatesubductsbeneathacontinentalplate,
whileinIslandArcsubductiontheoceanicplatesubductsbeneathanotheroceanicplate.
Modern-dayexamplesincludetheAleutianIslands,KurilIslands,Japan/JapaneseArchipelago,
Ryukyu,thePhilippines,SundaIslands,AndamanandNicobar,IzuIslands,BoninIslands,
MarianaIslands,BismarckArchipelago,SolomonIslands/Archipelago,NewHebrides,Tonga
Islands,Antilles,SouthSandwichIslands,Aegean/Hellenicarc,SouthAegeanarc.
PointBreakdown:
ExplainsthatCordilleran=continental-oceanicwhileIslandArc=oceanic-oceanic(2pointsfor
givingthedifference,butonly1pointiftheyjuststatewhatoneofthetwoare).1pointfora
correctexamplefromthelistabove(max3points).
SOCT2017DynamicPlanetChattahoochee–Key3
52. Highersilicacontentisassociatedwithahigherviscosity,lowereruptive/meltingtemperatures,
lowerdensity,ahigherwatercontent,moreexplosivevolcanoessuchascompositevolcanoes,
moresodium/potassium,andmoreorthoclasefeldspar/mica(eithermuscoviteor
biotite)/quartz/amphibole.Lowersilicacontentisassociatedwithalowerviscosity,higher
eruptive/meltingtemperatures,higherdensity,lowerwatercontent,lessexplosivevolcanoes
suchasshieldvolcanoes,moreiron/magnesium/calcium,andmorepyroxene/olivine.
PointBreakdown:
1pointforeachofthefollowing(max3points):
•
Highsilicameanshigherviscosity(ortheinverse)
•
Highsilicameanslowertemp.magma/lavaorlowereruptivetemp.(ortheinverse)
•
Highsilicameanslowerdensity(ortheinverse)
•
Highsilicameansmorewaterortheinverse)
•
Highsilicaisassociatedwithexplosive/compositevolcanoes(ortheinverse,less
explosiveshieldvolcanoes)
•
Highsilicahasmoresodiumorpotassium(ortheinverse,lowsilicahasmoreiron,
magnesium,andcalcium)
•
Highsilicahasmoreorthoclasefeldspar(orjustfeldspar),mica,biotite,muscovite,
quartz,andamphibole(ortheinverse,lowsilicahasmorepyroxeneandolivine)
Doesnothavetoexplainwhathappensatbothhighandlowamountsofsilica;eitheroneis
enoughforpoints.Forelementsandminerals(thelasttwo)theyonlyneedoneofthe
elements/mineralstogainthepoint;givingmoredoesn’tgiveanymorepoints.
53. Ridgepushistheforceappliedonaplateatadivergentboundarybygravityactedonthepartof
theplatethatisraisedupnearthespreadingsite,causingtheplatetoslide“downhill”away
fromtheboundary.Slabpullistheforcecausedbymantleconvectionactingonasubducting
sectionofaplate,pullingitdownintothemantle,whichcausesthepartoftheplateat
divergentboundarieselsewheretogetpulledawayfromthespreadingsite.Slabpullisalot
strongerthanridgepush.
SOCT2017DynamicPlanetChattahoochee–Key4
PointBreakdown:
Max5points
2pointsforacorrectdescriptionofridgepush(mustmentionthatitispoweredbygravity)
2pointsforacorrectdescriptionofslabpull(mustmentionthattheforcefromsubducting
sectionsaffectsdivergingsections).
1pointforstatingthatslabpullisstronger.
54. IsostasyistheeffectofthebuoyantforceofthemantleholdingupEarth’scrust.Becausethe
continentalcurstisthickerandlighterthanoceaniccrust,itsinksdeeperintothemantleand
thetopextendsfurtherupwhiletheoceaniccrusthasalowerelevationsurface.Thisiswhat
causesoceanwatertocollectonoceaniccrust.
PointBreakdown:
Max3points
1pointforidentifyingisostasyasbeingcausedbybuoyancy
1/2pointformentioningthesizedifferencesbetweencontinentalandoceaniccrust
1/2pointformentioningthedensitydifferencesbetweencontinentalandoceaniccrust
1pointformentioningthattheoceaniccrustsurfaceislowerthancontinentalcrustsurfaceasa
resultofisostasy
55. Stressisameasurementofthedisplacingforceactingonasolidorviscousliquid.Strainisthe
measurementoftheactualdisplacementofasolidorviscousliquid.Strainiscausedbythe
applicationofstress.
PointBreakdown:
Max3points
1pointformentioningthatstressmeasuresforce/pressure
1pointformentioningthatstrainmeasuresdisplacement/motion
1pointformentioningthatstresscausesstrain
56. Elasticdeformationisatypeofstrain/deformationinwhichthematerialisnotpermanently
deformed,andwillreturntoitsoriginalshapeoncetheforcethatcausedthedeformationis
SOCT2017DynamicPlanetChattahoochee–Key5
removed.Incontrast,ductiledeformationinvolvesapermanentdeformationofthematerial.
Brittlematerialsarethosewithavariableelasticityandlowductility,i.e.theybreaksoonafter
theystartstretching.Ductilematerialshavealowelasticityandahighductility,i.e.theystart
stretchwithasmallamountofforcebutwillcontinuestretchingforawhilebeforebreaking.
PointBreakdown
1pointforeachofthefollowing(max6points):
Total:23
•
Elasticdeformationistemporary
•
Ductiledeformationispermanent
•
Brittlematerialshavevariableelasticity
•
Brittlematerialshavelowductility
•
Ductilematerialshavelowelasticity
•
Ductilematerialshavehighductility
SOCT2017DynamicPlanetChattahoochee–Key6