牛耀龄系列讲座001：岩浆的起源演化与全球构造及地幔动力学过程001

大家下午好！牛耀龄(YaolingNiu)EarthSciences英国杜伦大学（DurhamUniversity）地球科学系教授兰州大学“中组部千人计划”特聘教授岩浆的起源，演化与全球构造（地幔动力学过程）MagmatisminOceanBasinsandMantleDynamics–Apetrologicandgeochemicalapproach岩浆的起源，演化与全球构造（地幔动力学过程）MagmatisminOceanBasinsandMantleDynamics–Apetrologicandgeochemicalapproach1.Basicconceptofmagmagenerationandevolution有关岩浆成因和演化的一些基本概念2.Somepetrologicandgeochemicalperspectivesofmantleplumes,oceanridges,plume-ridgeinteractionsandmantleconvection岩石学和地球化学观:地幔柱、洋中脊、地幔柱-洋中脊相互作用、地幔对流动等如果大家对我讲的内容感兴趣的话，我建议你们考虑加盟兰州大学，读研究生、做博士后、教书、育人：我保证你们会从事同样有趣的研究，但比我站得更高，看得更远,贡献更大！用岩石地球化学方法探讨大洋岩浆活动和地幔动力学过程MagmatisminOceanBasinsandMantleDynamics–APetrologicandGeochemicalApproachYaolingNiu(牛耀龄）1.Introduction–BasicConceptofMagmaGenerationandEvolution2.OceanRidgeMagmatism–NewPerspectivesfromGlobalMORBData3.OceanIslandmagmatism–NewPerspectivesfromGlobalOIBData4.Plume-RidgeInteractions–Apetrologic/geochemicalperspective2011.10西安“全国岩石学与地球动力学年会会前讲座”6.Mesozoic/Cenozoiclithospherethinning&volcanismineasternChina:Aspecialconsequenceofplatetectonics5.MORBGeochemistryandContinentalCrustGrowth1.Introduction–BasicConceptofMagmaGenerationandEvolution2011.10西安“全国岩石学与地球动力学年会会前讲座”Stone,S.&Y.L.Niu,2009.Originofcompositionaltrendsinclinopyroxeneofoceanicgabbrosandgabbroicrocks:AcasestudyusingdatafromODPHole735B,JournalofVolcanologyandGeothermalResearch,184,313-322.Niu,Y.L.&M.J.O’Hara,2009.MORBmantlehoststhemissingEu(Sr,Nb,TaandTi)inthecontinentalcrust:Newperspectivesoncrustalgrowth,crust-mantledifferentiationandchemicalstructureofoceanicuppermantle,Lithos,112,1-17.Niu,Y.L.,2005.Generationandevolutionofbasalticmagmas:SomebasicconceptsandahypothesisfortheoriginoftheMesozoic-CenozoicvolcanismineasternChina,GeologicalJournalofChinaUniversities,11,9-46.Niu,Y.L.,T.Gilmore,S.Mackie,A.Greig&W.Bach,2002.Mineralchemistry,whole-rockcompositionsandpetrogenesisofODPLeg176gabbros:Dataanddiscussion,InNatland,J.H.,Dick,H.J.B.,Miller,D.J.,andVonHerzen,R.P.(Eds.),ProceedingsoftheOceanDrillingProgram,ScientificResults,176,doi:10.2973/odp.proc.sr.176.011.2002,60pp.References:34KVpsVVs=0if100%meltpresentVswithmeltMelt,ifany,isinsignificantinthemantlebecauseofVs0Magmageneration:shallowprocess200kmSmithsonianInstitution,GlobalVolcanismProgram•ThelargestmountainbeltonEarth,~55,000kmlong,circlingtheglobe•Theverysitewhereoceancrust,66%surfaceofthesolidEarth,isbeingconstantlycreated.TheglobaloceanridgesystemMapadaptedfromNOAASmithsonianInstitution,GlobalVolcanismProgramConvergentPlateBoundary(Mariana,Tonga)IslandArcMid-OceanRidgeOceanIslandContinentalMarginArcIntraplate/DivergentPlateBoundary(EastAfrica,CFBofDeccan)RiftDivergentPlateBoundary(EPR,MAR)Intraplate(Hawaii,Reunion)ConvergentPlateBoundary(AndesinSouthAmerica)Twobasicprocessesofmagmaticrocks:1.Magmageneration:SolidMelt2.Magmaevolution:MeltSolidTwobasicprocessesofmagmaticrocks:1.Magmageneration:SolidMelt2.Magmaevolution:MeltSolidTemperaturePressure0%100%Subsolidus(100%solid)ASolid+LiquidBSuperliquidus(100%melt)CPartialMeltingMeltingofaRockTemperaturePressureAB-DPMechanismsofmeltgeneration:(1)Decompression(-DP,e.g.,MOR,hotspots/plumes)PartialMeltingDPH2O(3)AdditionofH2O(andalkalis)(DPH2O,e.g.,Arcs/subductionzones)DT(2)Heating(DT,e.g.,crustalmeltingforgranite/granitoidduetobasalticmagmaheatingorpossiblyinternalheatingduetoK-U-Thheataccumulation)Pressure(kbars)1100900700500150010000510152025Melts+solidSolidHydrous(H2O-saturated)solidiofcrustalrocksTemperature(°C)GraniteTonoliteBasalt050100150Melts+SolidDepth(km)DrySolidusCO2-H2OSolidusSolidWet(CO2+H2O-saturated)solidusofmantleperidotiteTemperature(°C)Mechanismsofmeltgeneration:1.Decompression(-DP,e.g.,MOR,hotspots/plumes)2.Heating(DT,e.g.,crustalmeltingforgranite/granitoidduetobasalticmagmaheatingorpossiblyinternalheatingduetoK-U-Thheataccumulation)3.AdditionofH2O(andalkalis)(DPH2O,e.g.,Arcs/subductionzones)4.Compression(DP,rare,butperhapssomecarbonatite,post-collisionalgranitoidsetc.)SourceRock(lherzolite)PetrologicalConsequenceofPartialMeltingApplicabletoothersystems:“fusiblemelt”and“refractoryresiduePMResidue-Refractory:highMg/Fe,lowSiO2(Harzburgite)Melt-fusible:lowMg/Fe,highSiO2(Picriteorpicriticbasalt)Partialmelting“transforms”onesinglerockintotworocks:(1)differentcompositions&(2)differentphysicalproperties•plagioclase(lowP)•spinel(mediumP)•garnet(highP)•amphiboles•phlogopite•baddeleyite•sulfidesetc.OlOpxCpxOrthopyroxiniteClinopyroxiniteDuniteHarzburgiteWebsteriteOlivineOrthopyroxeniteWehrliteOlivineWebsteriteLherzolite(Pyrolite)FerilePeridotiteOlOpxCpxDuniteHarzburgiteLherzolite(Pyrolite)ResidualPeridotitesFertile&residualperidotiteLherzolite=Harzburgite+basaltExperimentallyEstablishedMineralCompositionalSystematicsinPeridotiteMeltingResiduesF(wt.%)-ExtentofmeltingormeltextractionMg#=Mg/[Mg+Fe2+]inwholerockMg#-Oliv,Opx(Cpxifpresent)Al2O3-Opx(Cpxifpresent)Cr#=Cr/[Cr+Al]-SpinelMagmagenerationatdivergentplateboundaries:Mid-oceanridgesBackarcspreadingcentersContinentalriftsystemsGlobaloceanridges,backarcbasinsand4majorCenozoicContinentalrifts:RioGrande,Lak