LaserAblationICPMSofSiderophileandChalcophileElements激光烧蚀ICPMS的亲铁与硫元素精选课件

1、Laser Ablation ICP-MS of Siderophile and Chalcophile Elements in Mid-Oceanic Ridge GlassesEvelyn Martinique MervineDartmouth CollegeJuly 29th, 2019Mentor: Dr. Vincent Salters, Geochemistry第1页，共14页。OutlineGoals of the StudyBackgroundSample Selection and AnalysisDataConclusionsAcknowledgements第2页，共14页

2、。Goals of the StudyDevelop technique for measuring siderophile and chalcophile elements in glassesCompare LA-ICP-MS with traditional ICP-MSExamine residual apronsStudy how siderophile and chalcophile elements behave during crystal fractionation第3页，共14页。Background: Goldschmidts Classification of the

3、ElementsAtmophile: Noble gasesCovalently-bonded gasesSiderophile: Metals near and including iron in the periodic table Transition metalsExhibit metallic bondingChalcophile: Elements that bond to S, Se, Te, Sb, and AsTend to form covalent bondsLithophile: Elements which typically bond to oxygen in si

4、licates and oxidesTend to form ionic bonds第4页，共14页。Background:Why Study Siderophile and Chalcophile Elements?Scientists do not understand the behavior of most siderophile and chalcophile elements wellCan compare behavior of siderophile and chalcophile elements during magma genesis with the well-know

5、n behavior of major and other trace elementsWhat these elements may tell us:Oxidation state of the mantleBehavior of sulfur during magma genesisComposition of the Earths core第5页，共14页。Sample SelectionMid-Atlantic Ridge GlassesOn loan from Smithsonians Volcanic Glass CollectionThirty samples, divided

6、into two suites of fifteenEach suite represents samples related through crystal fractionationIndian Ridge GlassesAlready at the labUsed for method development第6页，共14页。Analysis Glass chips mounted in epoxy on a slideSlide polished to reveal flat glass surfaceSlide placed in sample holderLaser beam fi

7、red on sample, ablates sampleSample flows to the Finnigan ICP-MS, which ionizes the sampleElemental concentrations measured by separating ions based on mass in a magnetic field and counting them Laser HolesLaserMass Spectrometer4 mm第7页，共14页。Analysis:What We LearnedBlank LevelsConcentration LevelsLen

8、gth of measurementsTrack vs. spot analysisLA-ICP-MS data is comparable to solution ICP-MS dataFiring on residual aprons does not affect data qualityResidual ApronLaser Hole第8页，共14页。Data:Elements Measured in This StudyTable Source: /smyth/G30103.html= Elements analyzed in this study第

9、9页，共14页。Data: ConcentrationsIncompatible elements Preferentially included in the melt over the crystalline phaseDecrease with increasing MgO contentCompatible elementsPreferentially included in the crystalline phase over the meltIncrease with increasing MgO contentMgO concentration is inversely prop

10、ortional to amount of crystal fractionation Example: Incompatible Element Negative SlopeExample: Compatible Element Positive Slope第10页，共14页。Data: Crystal Fractionation TrendsCu is compatiblePb and Zn are incompatibleCopper (Cu)Zinc (Zn)Lead (Pb)第11页，共14页。Data: Crystal Fractionation TrendsBy comparin

11、gthe slopes of theelements plottedagainst MgO,can determinerelativecompatibilitiesHighly Incompatible: Mo, Pb, Pd, ZnIncompatible: Ga, Se, Cd, Co Compatible: Ni, Cu Insufficient Data: Ag, Re第12页，共14页。ConclusionsWere able to determine concentrations of many siderophile and chalcophile elements in mid

12、-ocean ridge glasses using LA-ICP-MSLA-ICP-MS data is comparable to ICP-MS dataFiring on residual aprons does not affect data qualityChalcophile Cu seems to behave compatiblyChalcophile Zn and Pb seem to behave incompatibly第13页，共14页。AcknowledgementsThanks to Vincent Salters, Roy Odom, Michael Bizimus, Munir Humayu