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应用铀系组分法测定湖泊沉积物的年龄是新的尝试。样品的各组分用不同浓度的溶剂提取,测试~(230)Th/~(232)Th和~(234)U/~(232)Th比值。分析结果表明,所有数据点有良好的线性关系,在溶解样品过程中没有发生铀和钍的同位素分馏效应。经过论证,三组分与二组分数学关系式等价;根据组分法模式测定的铀系年龄,B_194孔以18～66～144 kaBP为时间格架,反映了孔深25m以上沉积物古气候古环境演变历史。该结果与同岩芯的古地磁年龄近于一致,结合稳定同位素δ~(18)O和δ~(13)C数据与SPECMAP曲线可对比。
It is a new attempt to determine the age of lake sediments by uranium series component method. The components of the sample were extracted with different concentrations of solvents and the ~ (230) Th / ~ (232) Th and ~ (234) U / ~ (232) Th ratios were tested. The analysis results show that all the data points have a good linear relationship, and isotopic fractionation of uranium and thorium does not occur during the sample dissolution. Through the demonstration, the mathematical relationship between the three components and the two components is equivalent. Based on the uranium age measured by the component method, the B_194 pore scales are 1866 to 144 kaBP, reflecting the sediment paleozoic Climate ancient environment evolution history. This result is close to the paleomagnetic age of the same core. Comparing with the data of SPECMAP, the data of δ 18 O and δ 13 C are stable.