| Sm—Nd模式年龄和等时线年龄的适用性与局限性 |
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| 引用本文： | 李献华.Sm—Nd模式年龄和等时线年龄的适用性与局限性[J].地质科学,1996,31(1):97-104. |
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| 作者姓名： | 李献华 |
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| 作者单位： | 中国科学院广州地球化学研究所 广州 510640 |
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| 摘 要： | 陈江峰(1994)与杨晓松(1994)关于“二元混合体系的端元Sm-Nd同位素模式年龄计算方法”的讨论,提出了有关Sm-Nd同位素体系的基本原理和应用的一些问题。他们的讨论很有意义。近十年来,我国Sm-Nd同位素地球化学和地质年代学的研究和应用得到了迅速发展,并在岩石成因、壳幔演化、前寒武纪地质等研究中取得了大量的成果。同时,由于基础理论知识学习、实验技术推广、研究经费等方面诸多因素的限制,我国的Sm- Nd同位素研究和应用也出现了一些问题,这些问题在近年来发表的一些论文中不同程度地有所反映。本文在陈江峰和杨晓松讨论的基础上,着重对Sm-Nd模式年龄和等时线年龄的适用性和局限性及其有关问题进行讨论。
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| 关 键 词： | , |
| 收稿时间： | 1994-09-14 |
| 修稿时间： | 1994-09-14; |
A DISCUSSION ON THE MODEL AND ISOCHRON AGES OF Sm-Nd ISOTOPIC SYSTEMATICS:SUITABILITY AND LIMITATION |
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| Li Xianhua.A DISCUSSION ON THE MODEL AND ISOCHRON AGES OF Sm-Nd ISOTOPIC SYSTEMATICS:SUITABILITY AND LIMITATION[J].Chinese Journal of Geology,1996,31(1):97-104. |
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| Authors: | Li Xianhua |
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| Institution: | Guaugzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou, 510640 |
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| Abstract: | Sm-Nd isotopes has been widely employed in the crust-mantle evvolution,geochronology,petrogenesis,and Precambrian research etc,in Chinese literatures dunng the last decade.The problem of abuse and muisinterpretation of the Sin Nd isotopic systematics,however,resulted in false conclusions in some of recently published papers.This paper mainly reviews methodologies,sultabilities and limitations of the model and isochron ages of Sm-Nd systematics.The emphasis is placed on that the Sm/Nd ratio of samples close to a continentlike one is of importance to calculate Nd model age correctly.Nd model age may provide only an estimate of the average time that the matelal in the sample has been resident in the continental crust.Sm Nd isotopic systematics of fine-grained elastic sediments can be not only a sensitivve indicator of sedimentary provenance which could be related to the contemporaneous tectonic activities,but also useful to constrain the maximum age of the deposition of the sediments.Sm Nd isotopes has bothadvantages and dlsavantages in the constitution of isochron in the light of REE geochemical behaviors.Cautions must be evoked in interpretation of Sm Nd regression line,which may be or may not be isochron,errochron,and binary mixing line. |
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| Keywords: | , |
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