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Theroleofvolcano-iceinteractionsinunderstandingsubductionzonemagmatism WhitepapersubmissiontotheSZOWorkshopbyBenEdwards ThevastmajorityoftheglacierizedvolcanoesonEarthareinsubductionzones(Fig.1 fromEdwardsandKochtitzky2015;IcelandandAntarcticaarethetwonotableexceptions),yet littleworkhasbeendoneinthatsettingtounderstandhowinteractionsbetweeniceloading andunloadingmayhaveaneffectonmeltgenerationprocessesorstabilityofcrustalmagma storageareas(e.g.Gudmundsson,1986;Glazneretal.,Wattetal.2013). Figure1.Globaldistributionofglacierizedvolcanoes(EdwardsandKochtitzky2015). Whileitisdebatableastohowthickicemustbetoinfluencemantlemeltingprocesses,rapid crustalloadingandunloadingofevenahundredmetersoficecanhaveimportanteffectson localstressfields()andvolatilesaturation/vesiculation(Fig2;Edwardsetal.2015).Andgiven manyrecentexamplesfromtheCascades(MSH),Alaska(Redoubt,Pavlov),Iceland (Eyjafjallajokull),andSouthAmerica(NevadodelRuiz;Villarrica;Hudson),therealhazardsof theseinteractionspotentiallyhaveamuchlongerreachduetothefluidityoflaharsandthe potentialforthegenerationofextremelyfine ashfrommagma-waterinteractions.Especially inSouthAmerica,wherehighelevation glaciovolcanoesareimportantforyear-round watersuppliestomanycommunities,eruptions fromglacierizedvolcanoesposemany‘nontraditional’threats. Figure2.Relationshipbetweenfragmentation processesasafunctionofmagmaH2O concentrationandthicknessofoverlyingice. Theroleofvolcano-iceinteractionsinunderstandingsubductionzonemagmatism Whatisholdingbacksubductionzonesciencerelatedtoglaciovolcanism? • Mainlyalargergroupofscientiststrainedintheknowledgeofglaciovolcanism,willing andabletoworkinrelativelyextremefieldconditions; • Extremelyhighaccuracygeochronologytechniquesthatcanresolveeruptiontimingon thetime-scalesofclimatechange(1-10ky);and • Moreaccuratemodelsforsaturationofacompletesetofvolatilegasesatrelevant pressures(1-10MPa) WhatgrandsciencerequiresanewSZOinitiativerelatedtoglaciovolcanism? • Betterunderstandingoftheintegrated‘SZsystemscience’thatlinkslithospheric dynamics,cryospheric/hydrosphericdynamics,andatmosphericdynamics,andthatwill require:integratedresearchprojectsandteamsthatincludecrustal-andglacier-scale geophysics(highfieldcosts),andhighprecisiongeochemicalstudies(e.g.,ionprobe accessforCO2measurementsatconcentrationslessthan10ppm)thatwillalsohave highcosts;and • MainbenefitswillbeextractingamoredetailedclimaterecordfromSZvolcanoes(e.g. Wattetal.2013;HuybersandLangmuir2009;SmellieandEdwards2016)tobetter understandthefeedbackmechanismsbetweenclimateandvolcanism,aswellasbeing abletomakemuchmoreaccuratehazardmapsforproximalanddistallocationsnear glacierizedvolcanoes. Whatisnew,excitinganddoable? • Newistakingaholisticapproachtounderstandingglacierizedsubductionzone volcanoesasanintegratedsysteminfluencedbymorethanmagmaticconditionsofmelt generationandstorage; • Excitingislinkingprocessesatvastlydifferenttime-scales(platetectonics[106yr], Milankovichcycles[104-5yr],glaciermovements[104yr]anderuptiondynamics[101s] tofullyunderstandlinkagesfromthemantletotheatmosphereclimatechange;also understandinghowsuggestionsthatmoderndayclimatechangecontinuestoaffect ratesofmagmaproductioninIceland(e.g.Sigmundssonetal.2010)yethasapparently notleftascleararecordeveninactivesubductionzones(e.g.Wattetal.2013); Theroleofvolcano-iceinteractionsinunderstandingsubductionzonemagmatism • Doableismakingafullaccountingofthelinkedclimate-eruptionhistoriesof glaciovolcanoesinSZsettingswithdetailedfieldmappingandhighprecisionanalytical methods(geochronology,micro-analysisofH2O/CO2andothervolatilesinmelt inclusions,etc); • Glacierizedvolcanoeshavealonghistoryofhumaninteractionandmuchmorecanbe donetoinvestigatelinkswithmodernandancientsocieties(e.g.sourcesofobsidianin AK,Cascades,SA;religiousceremoniesofIncancultureand‘ice’mummies);and Glaciersatthesevolcanoesmayhavelongtermrecordsoftephra,frozeninice,that haveexperiencedlessdegradationfromsurficialweathering. • WhatformcantheSZOinitiativetakewithrespecttoglaciovolcanism? • Makingsuretotargetvolcanoesthathavebeenorareglacierizedfordetailedfield mappingandgeochronology;and • Developingintegratedteamsacrossdisciplines(volcanologists–geochemists- geochronologists–Quaternaryscientists–glaciologists)andestablishingageneric rubrictosystematizeanalysisofglacierizedvolcanoes,whichcanbeadaptedtospecific conditionsatlocationswithdifferentchallenges(e.g.volcanoesthatarepresently heavilyglacierizedmayhavestratigraphythatismuchlessaccessible,andmayrequire moregeophysicalsurveysoficeand/oricecoringtoquantifypresenticecoverandto recovertephrarecordsfromice) HowcantheSZOglaciovolcanismresearchreachscientists,studentsandthepublic? • Glacierizedvolcanoesareofspecialinteresttothepublicbecausemanyarerecognized ascriticalwatersourcesforcommunities(drinkingwaterforhumansandlivestock; waterforagriculture);and • Glacierizedvolcanoesarealsoofspecialinterestfortherecreationalopportunitiesthey provide(skiareas,iceclimbing,etc)andtheirproximitytolargepopulationcenters(e.g. Mt.RainierandSeattle;manyplacesinSouthAmerica). Theroleofvolcano-iceinteractionsinunderstandingsubductionzonemagmatism ReferencesCited • Edwards,B.R.,Kochtitzky,W.2015.Assessingtheglobalpotentialforvolcano-glacier interactions.GSAAbstractswithProgram,FallMeeting,Baltimore,MD.,Abst.#270455. • Edwards,B.R.,Gudmundsson,M.T.,Russell,J.K.,2015.Chapter20.Glaciovolcanism.In: Sigurdsson,H.,Houghton,B.,Rymer,H.,Stix,J.,McNutt,S.(Eds.),TheEncyclopediaof Volcanoes,377–393. • Glazner,A.F.,Manley,C.R.,Marron,J.S.andRojstaczer,S.1999.Fireorice: anticorrelationofvolcanismandglaciationinCaliforniaoverthepast800,000years. GeophysicalResearchLetters,26,1759–1762. • Gudmundsson,A.1986.Mechanicalaspectsofpost-glacialvolcanismandtectonicsof theReykjanesPeninsula,SouthwestIceland.JournalofGeophysicalResearch,91, 12,711–12,721. • Huybers,P.andLangmuir,C.2009.Feedbackbetweendeglaciation,volcanismand atmosphericCO2.EarthandPlanetaryScienceLetters,286,479–491. • Sigmundsson,F,Pinel,V,Lund,B.,Albino,F.,Pagli,C.,Geirsson,H.andSturkell,E.2010. Climateeffectsonvolcanism:influenceonmagmaticsystemsofloadingandunloading fromicemassvariations,withexamplesfromIceland.PhilosophicalTransactionsofthe RoyalSociety,A368,2519–34. • Smellie,J.L.,Edwards,B.R.2016.GlaciovolcanismonEarthandMars:products, processesandpaleoclimateimplications.CambridgeUniversityPress:Cambridge,ISBN 9781107037397,490p. • Watt,S,Pyle,D,Mather,T2013.Thevolcanicresponsetodeglaciation:evidencefrom glaciatedarcsandareassessmentofglobaleruptionrecords.Earth-ScienceReviews, 122,77-102.