Moraine | National Geographic Society

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A moraine is material left behind by a moving glacier. This material is usually soil and rock. Just as rivers carry along all sorts of ... ResourceLibraryENCYCLOPEDICENTRYResourceLibraryENCYCLOPEDICENTRYMoraineMoraineEncyclopedicentry.Amoraineismaterialleftbehindbyamovingglacier.Thismaterialisusuallysoilandrock.Grades5-12+SubjectsEarthScience,Geography,PhysicalGeographyPoweredbyEncyclopedicEntryVocabularyAmoraineismaterialleftbehindbyamovingglacier.Thismaterialisusuallysoilandrock.Justasriverscarryalongallsortsofdebrisandsiltthateventuallybuildsuptoformdeltas,glacierstransportallsortsofdirtandbouldersthatbuilduptoformmoraines.Togetabetterideaofwhatmorainesare,pictureyourselfwithatoybulldozeronalawnthathasabunchofdryleavesalloverit.Whenyourunthebulldozerthroughtheleaves,someofthemgetpushedaside,someofthemgetpushedforward,andsomeofthemleaveinterestingpatternsonthegrass.Nowthinkofthesepatternsandpilesofpushed-awayleaves—moraines—stretchingforkilometersontheEarth.Morainesonlyshowupinplacesthathave,orusedtohave,glaciers.Glaciersareextremelylarge,movingriversofice.Glaciersshapethelandscapeinaprocesscalledglaciation.Glaciationcanaffecttheland,rocks,andwaterinanareaforthousandsofyears.Thatiswhymorainesareoftenveryold.Morainesaredividedintofourmaincategories:lateralmoraines,medialmoraines,supraglacialmoraines,andterminalmoraines.LateralMoraineAlateralmoraineformsalongthesidesofaglacier.Astheglacierscrapesalong,ittearsoffrockandsoilfrombothsidesofitspath.Thismaterialisdepositedaslateralmoraineatthetopoftheglacier’sedges.Lateralmorainesareusuallyfoundinmatchingridgesoneithersideoftheglacier.Theglacierpushesmaterialupthesidesofthevalleyataboutthesametime,solateralmorainesusuallyhavesimilarheights.Ifaglaciermelts,thelateralmorainewilloftenremainasthehighrimsofavalley.MedialMoraineAmedialmoraineisfoundontopofandinsideanexistingglacier.Medialmorainesareformedwhentwoglaciersmeet.Twolateralmorainesfromthedifferentglaciersarepushedtogether.Thismaterialformsonelineofrocksanddirtinthemiddleofthenew,biggerglacier.Ifaglaciermelts,themedialmoraineitleavesbehindwillbealongridgeofearthinthemiddleofavalley.SupraglacialMoraineAsupraglacialmoraineismaterialonthesurfaceofaglacier.Lateralandmedialmorainescanbesupraglacialmoraines.Supraglacialmorainesaremadeupofrocksandearththathavefallenontheglacierfromthesurroundinglandscape.Dustanddirtleftbywindandrainbecomepartofsupraglacialmoraines.Sometimesthesupraglacialmoraineissoheavy,itblockstheviewoftheiceriverunderneath.Ifaglaciermelts,supraglacialmoraineisevenlydistributedacrossavalley.GroundMoraineGroundmorainesoftenshowupasrolling,strangelyshapedlandcoveredingrassorothervegetation.Theydon’thavethesharpridgesofothermoraines.Agroundmoraineismadeofsedimentthatslowlybuildsupdirectlyunderneathaglacierbytinystreams,orastheresultofaglaciermeetinghillsandvalleysinthenaturallandscape.Whenaglaciermelts,thegroundmoraineunderneathisexposed.Groundmorainesarethemostcommontypeofmoraineandcanbefoundoneverycontinent.TerminalMoraineAterminalmoraineisalsosometimescalledanendmoraine.Itformsattheveryendofaglacier,tellingscientiststodayimportantinformationabouttheglacierandhowitmoved.Ataterminalmoraine,allthedebristhatwasscoopedupandpushedtothefrontoftheglacierisdepositedasalargeclumpofrocks,soil,andsediment.Scientistsstudyterminalmorainestoseewheretheglacierflowedandhowquicklyitmoved.Differentrocksandmineralsarelocatedinspecificplacesintheglacier’spath.Ifamineralthatisuniquetoonepartofalandscapeispresentinaterminalmoraine,geologistsknowtheglaciermusthaveflowedthroughthatarea.FastFactMorainesofKilimanjaroMorainelandscapesarefoundallovertheworldandarestillbeingformed.GlaciersintheChugachMountains,neartheArcticCircleintheU.S.stateofAlaska,makefreshmorainedepositseveryday.Meanwhile,themeltingsnowsonTanzania'sMountKilimanjaroareleavingfreshmoraineinequatorialAfrica.FastFactThat'sNoSpeedBumpKaskawulshGlacierinCanadahasaridgeofmedialmorainethatstretchesonewholekilometer(0.6miles)wide.ArticleStateofPennsylvania:MoraineStateParkTheGeographySite:GlacialMoraineCreditsMediaCreditsTheaudio,illustrations,photos,andvideosarecreditedbeneaththemediaasset,exceptforpromotionalimages,whichgenerallylinktoanotherpagethatcontainsthemediacredit.TheRightsHolderformediaisthepersonorgroupcredited.WritersKimRutledgeMelissaMcDanielSantaniTengHilaryHallTaraRamroopErinSproutJeffHuntDianeBoudreauHilaryCostaIllustratorsMaryCrooks,NationalGeographicSocietyTimGuntherEditorsJeannieEvers,EmdashEditing,EmdashEditingKaraWestEducatorReviewerNancyWynneProducerNationalGeographicSocietyotherLastUpdatedJuly15,2022UserPermissionsForinformationonuserpermissions,pleasereadourTermsofService.Ifyouhavequestionsaboutlicensingcontentonthispage,pleasecontactngimagecollection@natgeo.comformoreinformationandtoobtainalicense.Ifyouhavequestionsabouthowtociteanythingonourwebsiteinyourprojectorclassroompresentation,pleasecontactyourteacher.Sheorhewillbestknowthepreferredformat.Whenyoureachouttohimorher,youwillneedthepagetitle,URL,andthedateyouaccessedtheresource.MediaIfamediaassetisdownloadable,adownloadbuttonappearsinthecornerofthemediaviewer.Ifnobuttonappears,youcannotdownloadorsavethemedia.TextTextont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