moraine | geology - Encyclopedia Britannica

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moraine, accumulation of rock debris (till) carried or deposited by a glacier. The material, which ranges in size from blocks or boulders (usually faceted ... moraine TableofContents moraine Introduction FastFacts RelatedContent Media Images More MoreArticlesOnThisTopic Contributors ArticleHistory Home Geography&Travel PhysicalGeographyofLand moraine geology Actions Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/science/moraine GiveFeedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). FeedbackType Selectatype(Required) FactualCorrection Spelling/GrammarCorrection LinkCorrection AdditionalInformation Other YourFeedback SubmitFeedback Thankyouforyourfeedback Oureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle. JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyourwork! ExternalWebsites WelcometoHanksville-GlacialMoraine Print Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/science/moraine Feedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). FeedbackType Selectatype(Required) FactualCorrection Spelling/GrammarCorrection LinkCorrection AdditionalInformation Other YourFeedback SubmitFeedback Thankyouforyourfeedback Oureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle. JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyourwork! ExternalWebsites WelcometoHanksville-GlacialMoraine By TheEditorsofEncyclopaediaBritannica • EditHistory TableofContents moraine Seeallmedia RelatedTopics: medialmoraine groundmoraine terminalmoraine lateralmoraine recessionalmoraine ...(Showmore) Seeallrelatedcontent→ moraine,accumulationofrockdebris(till)carriedordepositedbyaglacier.Thematerial,whichrangesinsizefromblocksorboulders(usuallyfacetedorstriated)tosandandclay,isunstratifiedwhendroppedbytheglacierandshowsnosortingorbedding.Severalkindsofmorainesarerecognized:Agroundmoraineconsistsofanirregularblanketoftilldepositedunderaglacier.Composedmainlyofclayandsand,itisthemostwidespreaddepositofcontinentalglaciers.Althoughseldommorethan5metres(15feet)thick,itmayattainathicknessof20m. ReadMoreonThisTopic glaciallandform:Moraines Asaglaciermovesalongavalley,itpicksuprockdebrisfromthevalleywallsandfloor,transportingitin,on,orundertheice.As... Aterminal,orend,moraineconsistsofaridgelikeaccumulationofglacialdebrispushedforwardbytheleadingglacialsnoutanddumpedattheoutermostedgeofanygiveniceadvance.Itcurvesconvexlydownthevalleyandmayextendupthesidesaslateralmoraines.Itmayappearasabeltofhillygroundwithknobsandkettles.Alateralmoraineconsistsofdebrisderivedbyerosionandavalanchefromthevalleywallontotheedgeofaglacierandultimatelydepositedasanelongateridgewhentheglacierrecedes.Amedialmoraineconsistsofalong,narrowlineorzoneofdebrisformedwhenlateralmorainesjoinattheintersectionoftwoicestreams;theresultantmoraineisinthemiddleofthecombinedglacier.Itisdepositedasaridge,roughlyparalleltothedirectionoficemovement. Arecessionalmoraineconsistsofasecondaryterminalmorainedepositedduringatemporaryglacialstandstill.Suchdepositsrevealthehistoryofglacialretreatsalongthevalley;insomeinstances10ormorerecessionalmorainesarepresentinagivenvalley,andtheagesofgrowingtreesorothersourcesofdatesprovideachronologyofglacialmovements. GetaBritannicaPremiumsubscriptionandgainaccesstoexclusivecontent. SubscribeNow ThisarticlewasmostrecentlyrevisedandupdatedbyAmyTikkanen.

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