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热电离质谱铀系法测定碳酸盐标样 总被引:5,自引:0,他引:5
用高精度热电离质谱(TIMS)铀系法测定碳酸盐标样的年龄,测定结果与α谱仪铀系法进行比较,铀含量和年龄值均吻合。方法对U的回收率可达95%,Th为92%。TIMS铀系法具有样品用量少、测试时间短、精度高的优点。 相似文献
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近10年来国际上用热电离质谱代替α谱仪测定不平衡铀系样品的年龄,在造礁珊瑚、洞穴堆积物、年轻火山岩和湖泊沉积物等领域已取得了显著的成果。该技术有明显的优点,如样品用量少,测试时间短,测量精度高,测年范围宽,是中更新世至全新世以来有效的测年方法之一,可为全球变化研究提供高精度和高灵敏度的年龄谱,展示了热电离质谱技术如同加速器质谱技术一样,有广阔的应用前景。我们曾用MAT-262质谱仪对国内石笋标样(GBW04412,GBW04413)和国际珊瑚标样(RKM-4)进行过测试,取得了与标准值一致的结果。 相似文献
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近10年来国际上用热电离质谱代替α谱仪测定不平衡铀系样品的年龄,在造礁珊瑚、洞穴堆积物、年轻火山岩和湖泊沉积物等领域已取得了显著的成果。该技术有明显的优点,如样品用量少,测试时间短,测量精度高,测年范围宽,是中更新世至全新世以来有效的测年方法之一,可为全球变化研究提供高精度和高灵敏度的年龄谱,展示了热电离质谱技术如同加速器质谱技术一样,有广阔的应用前景。我们曾用MAT-262质谱仪对国内石笋标样(GBW04412,GBW04413)和国际珊瑚标样(RKM-4)进行过测试,取得了与标准值一致的结果。 相似文献
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应用同位素稀释法热电离质谱(TIMS)技术测定珊瑚礁的高精度铀系年龄。通过对BarbadosⅢ、Ⅳ阶地等样品分析,RendezvousHil和Curacao+6m的TIMS年龄分别为129.2±1.2kaB.P.和125.4±1.1kaB.P.,对应深海沉积物氧同位素第5期5e段的高海面;Kendal山阶地为208.1±1.9kaB.P.,可能代表7c间冰期高海平面的时代。该结果与Edwards等测定同一阶地的年龄一致,与α谱法数据在误差范围内吻合。另外,探讨了初始铀同位素比值的变化,并对TIMS年龄的可靠性做了评价。 相似文献
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80年代中期发展起来的高精度、高灵敏度不平衡铀系热电离质谱定年新技术是同位素定年技术的一次革命性突破,并已在古气候、古环境、古海洋、考古学以及近代火山—岩浆作用研究中取得了一系列重要成果,本文介绍了这方面的研究进展。这一新技术已引起越来越广泛的重视,显示出巨大的应用前景。尽快开展不平衡铀系热电离质谱定年技术的应用,对提高我国的高分辩率第四纪年代学分析技术和应用研究水平有重要意义。 相似文献
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不平衡铀系定年的新技术突破——高精度、高灵敏度238U-234U-230Th同位素质谱测定和应用 总被引:3,自引:0,他引:3
80年代中期发展起来的高精度、高灵敏度不平衡铀系热电离质谱定年新技术是同位素定年技术的一次革命性突破,并已在古气候、古环境、古海洋、考古学以及近代火山—岩浆作用研究中取得了一系列重要成果,本文介绍了这方面的研究进展。这一新技术已引起越来越广泛的重视,显示出巨大的应用前景。尽快开展不平衡铀系热电离质谱定年技术的应用,对提高我国的高分辩率第四纪年代学分析技术和应用研究水平有重要意义。 相似文献
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用高精度、高灵敏度不平衡铀系热电离质谱(TIMS)法测定第卤纪地质年龄,并已在古气候、古环境、考古学以及近代活动火山作用的研究中取得了一系列重要成果。本文介绍了我们用MAT-262质谱仪对石笋、珊瑚进行测试并取得比较满意结果的情况。 相似文献
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In situ U-series dating by laser-ablation multi-collector ICPMS: new prospects for Quaternary geochronology 总被引:2,自引:0,他引:2
Stephen M. Eggins Rainer Grün Malcolm T. McCulloch Alistair W.G. Pike John Chappell Les Kinsley Graham Mortimer Michael Shelley Colin V. Murray-Wallace Christoph Sptl Lois Taylor 《Quaternary Science Reviews》2005,24(23-24):2523-2538
The capabilities and potential applications of in situ dating of Quaternary materials using laser ablation-MC-ICPMS are explored. 234U/238U and 230Th/234U can be measured with precision sufficient for dating at a spatial resolution of 100 μm or better in samples that contain as a little as 1 ppm uranium. Moreover, U and Th concentrations and U-series isotope ratios can be continuously profiled to determine changes in age that occur with sample growth (e.g. in speleothems). These capabilities additionally permit the dating of bones, teeth and possibly molluscs, which are subject to post-mortem open-system behaviour of U-series isotopes, and can be employed to elucidate processes of U-series migration during weathering and diagenesis. A drawback of laser ablation-MC-ICPMS is that it cannot in general provide U-series age estimates with the high precision and accuracy of conventional TIMS or solution MC-ICPMS methods. However, sample preparation is straightforward, the amount of sample consumed negligible, and it can be used to rapidly characterise or screen and select samples from which more precise and accurate dates can be obtained using conventional methods. Given further instrumental developments and the establishment of suitable matrix-matched standards for carbonates and other materials, we foresee that laser ablation-MC-ICPMS will play an increasingly important role in Quaternary dating research. 相似文献
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Jean Louis Birck 《Geostandards and Geoanalytical Research》2001,25(2-3):253-259
This paper illustrates that sample size cannot be reduced below a theoretical limit and still achieve the highest precision obtainable on modern mass spectrometers. Reproducibility at the few ppm level is achievable and is related essentially to ion counting statistics. The number of atoms necessary to carry out such measurements is related directly to the sensitivity of the instrumentation. As most of the elements of interest are not major constituents of natural silicates, a lower limit to the size of the starting sample is assessed. Even for a number of elements for which very high ion per atom yields are attained by TIMS, minimum sample mass is an important limiting factor for precious or rare samples and may reduce the scientific output of experiments or place a major constraint on the sampling strategy itself. For rare meteorites or individual Martian samples expected to be returned in amounts at the gramme scale for rocks or at the microgramme scale for dust, the high sensitivity of TIMS is a requirement. Nevertheless, a compromise has to be found between sample consumption and the minimal desirable precision for a useful isotopic measurement. 相似文献
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Global change has become a hot spot in Quaternary geology,and high-precision,high-sensitivity dating is also an urgent problem which needs to be solved.This paper presents some achievements in U-servies dating of marine corals by thermal ionization mass spectrometry (TIMS) and its application to the study of paleo-environments.Recently,coral samples were determined for their ages on a MAT-262 mass spectrometer and satisfactory results have been obtained. 相似文献
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高精度质谱计在同位素地球化学的应用前景 总被引:22,自引:0,他引:22
微量地质样品的高精度同位素比值测试已经成为地质和环境科学等领域极其重要的研究手段.新型固体热电离质谱计以其高精度和高灵敏度, 将在同位素年代学和地球化学领域有广阔的应用前景.报道采用IsoProbeT质谱计测量标准物质溶液的结果.测量锶标准物质NBS987和钕标准物质Ames分别获得平均87Sr/86Sr比值0.710 241 8±0.000 005 1和平均143Nd/144Nd比值0.512 148 4±0.000 002 9, 内部精度可达0.000 3%.微量锶标准物质(0.3~1 ng) 的同位素比值测量内部精度可以优于0.003%.结合低本底化学流程, 实现了微量地质样品的高精度同位素比值测试.这一结合将有效地促进单颗粒矿物年代学和同位素示踪在岩浆岩、变质岩、矿床、构造岩研究的应用. 相似文献