主量元素地球化学

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1、MajorElements“Wet-chems”:gravimetric/volumetricMajorElementsModernSpectroscopicTechniquesFigure8-1.Thegeometryoftypicalspectroscopicinstruments.FromWinter(2001)AnIntroductiontoIgneousandMetamorphicPetrology.PrenticeHall.Majorelements:usuallygreaterthan1%SiO2Al2O3FeOMgOCaONa2OK2OH

2、2OMinorelements:usually0.1-1%TiO2MnOP2O5CO2Traceelements:usually<0.1%everythingelseElementWt%OxideAtom%O60.8Si59.321.2Al15.36.4Fe7.52.2Ca6.92.6Mg4.52.4Na2.81.9AbundanceoftheelementsintheEarth’scrustAtypicalrockanalysisWt.%OxidestoAtom%ConversionOxideWt.%MolWt.AtompropAtom%SiO249.

3、2060.090.8212.25TiO21.8495.900.020.29Al2O315.74101.960.314.62Fe2O33.79159.700.050.71FeO7.1371.850.101.48MnO0.2070.940.000.04MgO6.7340.310.172.50CaO9.4756.080.172.53Na2O2.9161.980.091.40K2O1.1094.200.020.35H2O+0.9518.020.111.58(O)4.8372.26Total99.066.69100.00Mustmultiplyby#ofcatio

4、nsinoxideTableChemicalanalysesofsomerepresentativeigneousrocksPeridotiteBasaltAndesiteRhyolitePhonoliteSiO242.2649.2057.9472.8256.19TiO20.631.840.870.280.62Al2O34.2315.7417.0213.2719.04Fe2O33.613.793.271.482.79FeO6.587.134.041.112.03MnO0.410.200.140.060.17MgO31.246.733.330.391.0

5、7CaO5.059.476.791.142.72Na2O0.492.913.483.557.79K2O0.341.101.624.305.24H2O+3.910.950.831.101.57Total98.7599.0699.399.5099.23CIPWNormModeisthevolume%ofmineralsseenNormisacalculated“idealized”mineralogyVariationDiagramsHowdowedisplaychemicaldatainameaningfulway?Bivariate(x-y)diagra

6、msHarkerdiagramforCraterLakeFigure8-2.Harkervariationdiagramfor310analyzedvolcanicrocksfromCraterLake(Mt.Mazama),OregonCascades.DatacompiledbyRickConrey(personalcommunication).Bivariate(x-y)diagramsHarkerdiagramforCraterLakeFigure8-2.Harkervariationdiagramfor310analyzedvolcanicro

7、cksfromCraterLake(Mt.Mazama),OregonCascades.DatacompiledbyRickConrey(personalcommunication).橄榄石(Fe,Mg)2SiO4SiO239%MgO40%斜方辉石(Fe,Mg)2Si2O6SiO254%普通辉石(CaNaK)…Al(AlSi)2O6SiO248%角闪石CaNaK…(Al4O11)2(OH…)SiO239%黑云母KAl…(AlSiO3O10)(OH…)SiO239%K2O10%石英SiO2SiO2100%钾长石KAlSi3O8SiO271%K2O8%斜长石

8、NaAlSi3/CaAl2Si2O8SiO268-50%霞石NaAlSiO4Si