Precise measurement of stable (δ
88/86Sr) and radiogenic (87Sr/86Sr) strontium isotope ratios in geological standard reference materials using MC-ICP-MS |
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作者姓名: | MA JinLong WEI GangJian LIU Ying REN ZhongYuan XU YiGang YANG YongHong |
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作者单位: | State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences;CAS Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences |
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基金项目: | supported by the Chinese Ministry of Science and Technology Special Scheme (2009CB421206 and 2010CB808900);the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-138);the National Natural Science Foundation of China (40973008 and 41173006);contribution No.IS-1616 from GIGCAS |
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摘 要: | A new method for high-precision measurements of stable (δ88/86Sr) and radiogenic (87Sr/86Sr) Sr isotope ratios was developed on the MC-ICP-MS using a standard-sample-standard bracketing protocol. By carefully monitoring and controlling the accumulation of the on-peak backgrounds (i.e. the carryover memory) on the instrument, our method can provide an external precision of around 0.010‰ to 0.014‰ for 88/86 Sr measurements. Such precision is comparable to that achieved by double-spike TIMS method (DS-TIMS), and 2-3 times better than those of the previously reported results by MC-ICP-MS without spiking. The results of the standard seawater IAPSO are also identical to those by DS-TIMS. However, our method is more advantageous, efficient and convenient to use for routine Sr isotopic analysis than the DS-TIMS method as there is no need to prepare and calibrate the 84Sr-87 Sr double spike. Using this method, we measured the δ88/86Sr values in a series of international geological rock standards, which show large variability, with the lowest value (0.20‰) registered in JG-2, a terrestrial granite, and the highest value (0.539‰) in UB-N, a serpentinite. This may provide an additional means for isotopic characterization of geological processes, adding a new dimension over the traditional use of radiogenic Sr isotopic ratio 87Sr/86Sr.
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关 键 词: | stable Sr isotopes δ88/86Sr 87Sr/86Sr IAPSO geological standards MC-ICP-MS |
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