| 铀系国际标准样鉴定结果讨论 |
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| 引用本文： | 夏明.铀系国际标准样鉴定结果讨论[J].地质科学,1984,0(1):13-25. |
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| 作者姓名： | 夏明 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 铀系国际标准样的鉴定是开展铀系方法的一项基础工作。其主要内容是测定实验流程中所必需使用示踪剂的参数,测试地质样品中各项同位素比值和年龄,检验各国铀系实验室的全部实验程序。
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| 关 键 词： | , |
| 收稿时间： | 1983-05-19 |
| 修稿时间： | 1983-05-19; |
DISCUSSION ON RESULTS OF THE URANIUM-SERIES INTERCOMPARISON PROJECT |
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| Xia Ming.DISCUSSION ON RESULTS OF THE URANIUM-SERIES INTERCOMPARISON PROJECT[J].Chinese Journal of Geology,1984,0(1):13-25. |
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| Authors: | Xia Ming |
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| Institution: | Institute of Geology, Academia Sinica, Beijing |
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| Abstract: | The Phases Ⅰ,Ⅱ and Ⅲ of the Uranium-Series Intercomparison Project (USIP) consist of the analysis of same natural carbonate samples by between-laboratories in defferent coutries,aim at checking against systematic errors in the procedure and age calculation,and prove the valid analytical technique for dating by U-series geochronology.A statistical analysis of USIP results-Phases Ⅰ,Ⅱ and Ⅲ,including U contents,230Th/234U,234U/238U activity ratios and 232U spike concentration as well as parameters,indicates a good interlaboratory agreement.Sources of total analytical errors can be divided into three types: (1) counting statistic,(2) the error caused by the chemical procedure,degree of spectral resolution and peak tail corrections,extent of sample homogeneity and spectral interpretation,and (3) radom uncertainty.Our laboratory is involved in the USIP Phases Ⅱ and Ⅲ.The results show that our data are in good agreeable with the “best estimate” mean values.Dissolution and chemical procedure and source preparation for carbonate samples are examined in detail in order to identify the reasons for variation in chemical yields,thus enabling consistently high yields to be achieved.Methods of the data-processing used in measurement of isotopic ratios and calculation,and determination of correcting factors have been carried out.This indicates that a standardization of age calculation procedures for U-series geochronology is required.The 232Th solution used as the spike in chemical procedure in order to attempt at determining the age of geological samples.The experimental results suggest that if the sample remained a closed system and U concentration was known,the approach to age-determination would be appropriated.In addition,two factors of influence,210Po and △228Th for determining the 232U concentration in the spike and dating geological samples are discussed here.The maxium influence of residual 228Th (△228Th) on the total counts of 232U can reach 2%.It is necessary to make a correction for △228Th.In some cases,where an uraninite is taken as the standard solution to calibrate to concentration of 232U,considerable amounts of 210Po in alpha-spectrum of uranium isotopes would cause unacceptable uncertainties. |
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| Keywords: | , |
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