磷灰石Sr-Nd同位素的激光剥蚀-多接收器电感耦合等离子体质谱微区分析
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摘要
磷灰石是常见的副矿物,具有较高的Sr-Nd含量和较低的Rb含量,对其微区Sr-Nd同位素组成的准确测定可以为精细地质作用过程的探讨提供重要的地球化学信息。激光剥蚀-多接收器电感耦合等离子体质谱(LA-MC-ICPMS)具有分析速度快、分析精度高和空间分辨率高的特点,特别适合大量细颗粒磷灰石样品的Sr-Nd同位素分析,而同位素干扰的精确扣除和仪器质量歧视校正是原位微区分析准确获得Sr-Nd同位素比值的关键。本文利用LA-MC-ICPMS技术,综合最新发表的Kr、Rb、稀土二价离子及钙聚合物对Sr同位素的干扰扣除方法和Sm对Nd同位素的干扰扣除方法,对仪器的质量歧视进行了校正,建立了磷灰石原位Sr-Nd同位素分析方法。用此方法对一个磷灰石国际标准样品Durango和两个实验室标准Apatite 1和PE进行了详细的Sr-Nd同位素测定,结果表明,对Sr-Nd含量足够高的磷灰石样品可以准确地获得其Sr-Nd同位素组成,测试结果与文献报道值或热电离质谱(TIMS)测试值在误差范围内一致,Sr同位素的测试精度<0.015%(2SD),Nd同位素的测试精度<0.005%(2SD),达到了国际同类实验室水平;且三个磷灰石标准样品同位素组成较为均一,都是理想的原位Sr-Nd同位素分析参考物质。
Apatite is a common accessory mineral,having a high Sr-Nd content and a low Rb content.The precise determination of micro-area Sr-Nd isotopic composition for apatite will provide important geochemical information for discussing the details of the geological process.Laser Ablation Multi-collector Inductively Coupled Plasma-Mass Spectrometry(LA-MC-ICPMS) technique has the characteristics of rapid analysis,high analytical precision and high spatial resolution,and is particularly suitable for Sr-Nd isotopic analysis of a large quantity of fine-grained apatite samples.The precise deduction of isotopic interference and calibration of instrument mass bias are crucial for in-situ analysis to obtain Sr-Nd isotopic ratio.In this article a method is described,which adopts LA-MC-ICPMS and combines with the newly published method for deduction of interferences,like Kr,Rb,divalent ions of REEs and calcium-containing polymer for Sr isotopes,Sm for Nd isotopes.The calibration of instrument mass bias is carried out,and the in-situ Sr-Nd isotopic analysis approach for apatite is established.The test results of Durango apatite standard,Apatite 1 and PE show that Sr-Nd isotopic composition of apatite sample with high Sr-Nd content can be accurately determined.The specific results are consistent with literature or the measured values by Thermal Ionization Mass Spectrometry(TIMS) within error.The measurement precision of Sr isotopes is <0.015%(2SD),and that of Nd isotopes is <0.005%(2SD).The established method is applied for Sr-Nd isotopic analysis of Durango apatite standard,Apatite 1 and PE(laboratory standard),respectively.The analysis results indicate that the Sr-Nd isotopic compositions of the three apatite samples are basically consistent,and can serve as ideal reference samples for in-situ Sr-Nd isotopic analysis.
Apatite is a common accessory mineral,having a high Sr-Nd content and a low Rb content.The precise determination of micro-area Sr-Nd isotopic composition for apatite will provide important geochemical information for discussing the details of the geological process.Laser Ablation Multi-collector Inductively Coupled Plasma-Mass Spectrometry(LA-MC-ICPMS) technique has the characteristics of rapid analysis,high analytical precision and high spatial resolution,and is particularly suitable for Sr-Nd isotopic analysis of a large quantity of fine-grained apatite samples.The precise deduction of isotopic interference and calibration of instrument mass bias are crucial for in-situ analysis to obtain Sr-Nd isotopic ratio.In this article a method is described,which adopts LA-MC-ICPMS and combines with the newly published method for deduction of interferences,like Kr,Rb,divalent ions of REEs and calcium-containing polymer for Sr isotopes,Sm for Nd isotopes.The calibration of instrument mass bias is carried out,and the in-situ Sr-Nd isotopic analysis approach for apatite is established.The test results of Durango apatite standard,Apatite 1 and PE show that Sr-Nd isotopic composition of apatite sample with high Sr-Nd content can be accurately determined.The specific results are consistent with literature or the measured values by Thermal Ionization Mass Spectrometry(TIMS) within error.The measurement precision of Sr isotopes is <0.015%(2SD),and that of Nd isotopes is <0.005%(2SD).The established method is applied for Sr-Nd isotopic analysis of Durango apatite standard,Apatite 1 and PE(laboratory standard),respectively.The analysis results indicate that the Sr-Nd isotopic compositions of the three apatite samples are basically consistent,and can serve as ideal reference samples for in-situ Sr-Nd isotopic analysis.
引文
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[16]Jochum K P,Wilson S A,Abouchami W,Amini M,Chmeleff J,Eisenhauer A,Hegner E,Iaccheri L M,Kieffer B,Krause J,McDonough W F,Mertz-KrausR,Raczek I,Rudnick R L,Scholz D,Steinhoefel G,Stoll B,Stracke A,Tonarini S,Weis D,Weis U,Woodhead J D.GSD-1G and MPI-DING referenceglasses for in situ and bulk isotopic determination[J].Geostandards and Geoanalytical Research,2010,35(2):193-226.
[17]Straub S M,Goldstein S L,Class C,Schmidt A,Gomez-Tuena A.Slab and mantle controls on the Sr-Nd-Pb-Hf isotope evolution of the post 42Ma Izu-Boninvolcanic arc[J].Journal of Petrology,2010,51(5):993-1026.
[18]Dilek Y,Furnes H,Shallo M.Geochemistry of theJurassic Mirdita Ophiolite(Albania)and the MORB toSSZ evolution of a marginal basin oceanic crust[J].Lithos,2008,100:174-209.
[19]Beier C,Turner S P,Sinton J M,Gill J B.Influence ofsubducted components on back-arc melting dynamics inthe Manus Basin,Geochem[J].Geochemistry,Geophysics,Geosystems,2010,11,Q0AC03,doi:10.1029/2010GC003037.
[20]Stouraiti C,Mitropoulos P,Tarney J,Berreiro B,McGrathA M,Baltatzis E.Geochemistry and petrogenesis oflate Miocene granitoids,Cyclades,southern Aegean:Nature of source components[J].Lithos,2010,114:337-352.
[21]Vroon P Z,Wagt B V D,Koornneef J M,Davies G R.Problems in obtaining precise and accurate Sr isotopeanalysis from geological materials using laser ablationMC-ICP-MS[J].Analytical and BioanalyticalChemistry,2008,390:465-476.
[22]Paton C,Woodhead J,Hergt J,Phillips D,Shee S.Srisotope analysis of Kimberlitic groundmass perovskitevia LA-MC-ICPMS[J].Geostandards andGeoanalyitical Research,2007,31:321-320.
[23]Waight T,Baker J,Peate D.Sr isotope ratio measure-ments by double-focusing MC-ICP-MS:Techniques,observations and pitfalls[J].International Journal ofMass Spectrometry,2002,221:229-244.
[24]Dubois J C,Retali G,Cesario J.Isotopic analysis ofrare earth elements by total vaporization of samples inthermal ionization mass spectrometry[J].InternationalJournal of Mass Spectrometry and Ion Processes,1992,120:163-177.
[25]Isnard H,Brennetot R,Caussignac C,Caussignac N,Chartier F.Investigations for determination of Gd andSm isotopic compositions in spent nuclear fuels samplesby MC ICPMS[J].International Journal of MassSpectrometry,2005,246:66-73.
[26]杨岳衡,张宏福,谢烈文,吴福元.多接收器电感耦合等离子体质谱精确测定钕同位素组成[J].分析化学,2007,35(1):71-74.
[27]McDowell F W,McIntosh W C,Farley K A.A precise40Ar-39Ar reference age for the Durango apatite(U-Th)/He and fission-track dating standard[J].Chemical Geology,2005,214:249-263.
[2]祝禧艳,陈福坤,杨一增,胡蓉.微区-微量样品Rb-Sr同位素分析技术及其应用前景[J].岩石学报,2010,26(1):325-332.
[3]Rehkamper M,Schonbachler M,Stirling C H.Multiplecollector ICP-MS:Introduction to instrumentation,measurement techniques and analytical capabilities[J].Geostandard Newsletter,2001,25:23-40.
[4]Ramos F C,Woff J A,Tollstrup D L.Measuring 87Sr/86Sr variation in minerals and groundmass frombasalts using LA-MC-ICPMS[J].Chemical Geology,2004,211:135-158.
[5]Woodhead J,Swearer S,Hergt J,Maas R.In situ Sr-isotope analysis of carbonates by LA-MC-ICPMS:Interference corrections,high spatial resolution and anexample from otolith studies[J].Journal of AnalyticalAtomic Spectrometry,2005,20:22-27.
[6]Yang Y H,Wu F Y,Wilde S A,Liu X M,Zhang Y B,Xie L W,Yang J H.In situ perovskite Sr-Nd isotopeconstrains on petrogenesis of the Mengyin kimberlites inthe North China Craton[J].Chemical Geology,2009,264:24-42.
[7]宗克清,刘勇胜,高长贵,袁洪林,陈海红.CCSD榴辉岩中磷灰石微区微量元素和Sr同位素组成研究[J].岩石学报,2007,23(12):3267-3274.
[8]杨岳衡,吴福元,谢烈文,杨进辉,张艳斌.地质样品Sr同位素激光原位等离子体质谱(LA-MC-ICPMS)测定[J].岩石学报,2009,25(12):3431-3441.
[9]Foster G L,Vance D.In situ Nd isotopic analysis ofgeological materials by laser ablation MC-ICP-MS[J].Journal of Analytical Atomic Spectrometry,2006,21:288-296.
[10]Foster G L,Carter A.Insights into the patterns andlocations of erosion in the Himalaya—A combinedfission-track and in situ Sm-Nd isotopic study of detritalapatite[J].Earth and Planet Science Letter,2007,257:407-418.
[11]McFarlane C R M,McCulloch M T.Coupling of in-situSm-Nd systematics and U-Pb dating of monazite andallanite with applications to crustal evolution studies[J].Chemical Geology,2007,245:45-60.
[12]Fisher C F,McFarlane C R M,Hanchar J M,SchmitzM D,Sylvester P J,Lam R,Longerich H P.Sm-Ndisotope systematics by laser ablation-multicollector-inductively coupled plasma mass spectrometry:Methodsand potential natural and synthetic reference materials[J].Chemical Geology,2011,284:1-20.
[13]杨岳衡,孙金凤,谢烈文,范宏瑞,吴福元.地质样品Nd同位素激光原位等离子体质谱(LA-MC-ICPMS)测定[J].科学通报,2008,53(5):568-576.
[14]Wu F Y,Yang Y H,Mitchell R H,Bellatreccia F,LiQ L,Zhao Z F.In situ U-Pb and Nd-Hf-(Sr)isotopicinvestigations of zirconolite and calzirtite[J].ChemicalGeology,2010,277:178-195.
[15]Donnelly C L,Griffin W L,Yang J H,O’Reilly S Y,Li Q L,Pearson N J,Li X H.In situ U-Pb dating andSr-Nd isotopic analysis of perovskite:Constraints on theage and petrogenesis of the Kuruman KimberliteProvince,Kaapvaal Craton,South Africa[J].Journalof Petrology,2012,53(12):2497-2522.
[16]Jochum K P,Wilson S A,Abouchami W,Amini M,Chmeleff J,Eisenhauer A,Hegner E,Iaccheri L M,Kieffer B,Krause J,McDonough W F,Mertz-KrausR,Raczek I,Rudnick R L,Scholz D,Steinhoefel G,Stoll B,Stracke A,Tonarini S,Weis D,Weis U,Woodhead J D.GSD-1G and MPI-DING referenceglasses for in situ and bulk isotopic determination[J].Geostandards and Geoanalytical Research,2010,35(2):193-226.
[17]Straub S M,Goldstein S L,Class C,Schmidt A,Gomez-Tuena A.Slab and mantle controls on the Sr-Nd-Pb-Hf isotope evolution of the post 42Ma Izu-Boninvolcanic arc[J].Journal of Petrology,2010,51(5):993-1026.
[18]Dilek Y,Furnes H,Shallo M.Geochemistry of theJurassic Mirdita Ophiolite(Albania)and the MORB toSSZ evolution of a marginal basin oceanic crust[J].Lithos,2008,100:174-209.
[19]Beier C,Turner S P,Sinton J M,Gill J B.Influence ofsubducted components on back-arc melting dynamics inthe Manus Basin,Geochem[J].Geochemistry,Geophysics,Geosystems,2010,11,Q0AC03,doi:10.1029/2010GC003037.
[20]Stouraiti C,Mitropoulos P,Tarney J,Berreiro B,McGrathA M,Baltatzis E.Geochemistry and petrogenesis oflate Miocene granitoids,Cyclades,southern Aegean:Nature of source components[J].Lithos,2010,114:337-352.
[21]Vroon P Z,Wagt B V D,Koornneef J M,Davies G R.Problems in obtaining precise and accurate Sr isotopeanalysis from geological materials using laser ablationMC-ICP-MS[J].Analytical and BioanalyticalChemistry,2008,390:465-476.
[22]Paton C,Woodhead J,Hergt J,Phillips D,Shee S.Srisotope analysis of Kimberlitic groundmass perovskitevia LA-MC-ICPMS[J].Geostandards andGeoanalyitical Research,2007,31:321-320.
[23]Waight T,Baker J,Peate D.Sr isotope ratio measure-ments by double-focusing MC-ICP-MS:Techniques,observations and pitfalls[J].International Journal ofMass Spectrometry,2002,221:229-244.
[24]Dubois J C,Retali G,Cesario J.Isotopic analysis ofrare earth elements by total vaporization of samples inthermal ionization mass spectrometry[J].InternationalJournal of Mass Spectrometry and Ion Processes,1992,120:163-177.
[25]Isnard H,Brennetot R,Caussignac C,Caussignac N,Chartier F.Investigations for determination of Gd andSm isotopic compositions in spent nuclear fuels samplesby MC ICPMS[J].International Journal of MassSpectrometry,2005,246:66-73.
[26]杨岳衡,张宏福,谢烈文,吴福元.多接收器电感耦合等离子体质谱精确测定钕同位素组成[J].分析化学,2007,35(1):71-74.
[27]McDowell F W,McIntosh W C,Farley K A.A precise40Ar-39Ar reference age for the Durango apatite(U-Th)/He and fission-track dating standard[J].Chemical Geology,2005,214:249-263.