Reproducing past subduction and mantle flow using high-resolution global convection models

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摘要 PlatesubductiondrivesboththeinternalconvectionandthesurfacegeologyofthesolidEarth.Despitetherapidincreaseofcomputationalpower,itremainschallengingforgeodynamicmodelstoreproducethehistoryofEarth-likesubductionandassociatedmantleflow.Here,basedonanadaptiveapproachofsequentialdataassimilation,wepresentahigh-resolutionglobalmodelsincethemid-Mesozoic.ThismodelincorporatesthethermalstructureandsurfacekinematicsoftectonicplatesbasedonarecentplatereconstructiontoreproducetheobservedsubductionconfigurationandEarth-likeconvection.Introductionoftemperature-andcomposition-dependentrheologyallowsforincorporationofmanynaturalcomplexities,suchasinitiationofsubductionzones,reversalofsubductionpolarity,anddetailedplate-boundarydynamics.Theresultantpresent-dayslabgeometrywellmatchesBenioffzonesandseismictomographyatdepths<1500km,makingitpossibletohindcastpastsubductiondynamicsandmantleflow.Forexample,themodelproducesaflatFarallonslabbeneathNorthAmericaduringtheLateCretaceoustoEarlyCenozoic,afeaturethathasbeengeodynamicallychallengingtoreproduce.Thishigh-resolutionmodelcanalsocapturedetailsofthe4-Devolutionofslabsandtheambientmantle,suchastemporallyandspatiallyvaryingmantleflowassociatedwithevolvingslabgeometryandbuoyancyflux,aswellastheformationofshallowslabtearsduetosubductionofyoungseafloorsandtheresultingcomplexmantledeformation.Suchageodynamicframeworkservestofurtherconstrainuncertainplatereconstructioninthegeologicalpast,andtobetterunderstandtheoriginofenigmaticmantleseismicfeatures.
机构地区 不详
出版日期 2018年03月13日(中国期刊网平台首次上网日期,不代表论文的发表时间)
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