Variations in carbon isotopic composition in the subcontinental lithospheric mantle beneath the Yangtze and North China Cratons: Evidence from in-situ analysis of diamonds using SIMS
Variations in carbon isotopic composition in the subcontinental lithospheric mantle beneath the Yangtze and North China Cratons: Evidence from in-situ analysis of diamonds using SIMS
复制标题
扬子和华北克拉通下次大陆岩石圈地幔碳同位素组成的变化：利用SIMS对钻石进行原位分析的证据
DOI：
10.1007/s11434-012-5509-0
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发表时间：
2013
影响因子：
--
通讯作者：
Peng ShuYi
中科院分区：
文献类型：
--
作者：
Qin SheCai;Qiu ZhiLi;Lu TaiJin;Stern, Richard;Stachel, Thomas;Sun Yuan;Zhang Jian;Ke Jie;Peng ShuYi
华北板块和扬子板块之下的陆下岩石圈地幔组成和演化是当前中国地质研究的热点，金刚石碳同位素组成是研究陆下岩石圈地幔过程最直接的方法之一。本文采用原位二次离子质谱（SIMS）技术对华北地区山东、辽宁和扬子地区湖南金刚石不同内生长带的碳同位素组成进行了分析。结果表明，华北陆坡金刚石的碳同位素范围与扬子陆坡金刚石的碳同位素范围有较大差异，前者的碳同位素范围为-6.0/‰ ~-2.0 ‰（相对于VPDB），其核心区域的平均值为-3.0 ‰，这与全球橄榄岩钻石一致;而扬子区金刚石的碳同位素范围为-8.6 ‰ ~-3.0 ‰，核部平均值为-7.4 ‰，与全球榴辉岩金刚石更为一致。在所研究的三个金刚石产地中，金刚石内部不同生长带之间的碳同位素比值变化是不同的。碳同位素组成的变化与金刚石溶解和新生阶段有明显的相关性，而δ 13 C与内部包裹体无相关性。这些变化表明，在金刚石结晶过程中，地幔流体的碳同位素组成发生了变化，地幔碳储层中碳同位素组成的不均匀性对金刚石碳同位素组成及其变化的控制作用比碳同位素分馏作用更为重要。此外，原位氮分析的初步结果表明，核和外部生长带之间的碳同位素组成的变化与氮丰度无关，这意味着要么钻石结晶在一个开放的环境中，或地幔流体中的碳同位素组成和氮含量由其他尚未了解的因素控制。实验结果表明，华北板块和扬子板块地幔中控制金刚石形成的交代流体的碳同位素组成和来源不同。
The components and evolution of subcontinental lithospheric mantle beneath the North China Craton and the Yangtze Craton is a current topic in the geological study of China and the carbon isotopic composition of diamond is one of the most direct probes into cratonic lithospheric mantle processes. In this paper, in-situ SIMS (Secondary Ion Mass Spectrometry) techniques were used to analyze the carbon isotope compositions at different internal growth zones of diamonds from Shandong and Liaoning in the North China Craton and Hunan in the Yangtze Craton. It was found that the carbon isotopic range of diamonds from the North China Craton are rather distinct from those of the Yangtze Craton; the former has a range of −6.0/‰ to −2.0‰ (relative to VPDB) with an average value of −3.0‰ in their core areas, which is consistent with global peridotitic diamonds; the diamonds from the Yangtze Craton, however, have a carbon isotopic range from −8.6‰ to −3.0‰ with an average value of −7.4‰ in their core areas, being more consistent with global eclogitic diamonds. The variations of carbon isotope ratios between different internal growth zones in individual diamonds were different in the three diamond localities studied. There was a clear correlation between changes in carbon isotopic composition and phases of diamond dissolution and new growth, while no correlation was observed between δ13C and internal inclusions. The variations suggest that the carbon isotopic compositions of mantle fluids were changing during the process of diamond crystallization, and that the heterogeneity of the carbon isotopic composition in mantle carbon reservoirs was a more important factor than carbon isotope fractionation in controlling the carbon isotopic compositions and their variation in diamonds. In addition, the preliminary results of in-situ nitrogen analyses demonstrated that the variation of carbon isotopic compositions between the core and outer growth zones does not correlate with nitrogen abundances, implying either that diamonds crystallized in an open environment or that the carbon isotopic composition and nitrogen contents in mantle fluids were controlled by other, not yet understood factors. The experimental results provide hints that the isotopic composition of carbon and its original sources were different in metasomatic fluids controlling diamond formation in the mantle beneath the North China Craton and the Yangtze Craton.
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影响因子：
3.8
作者：
Xian‐Hua Li;Jian-xin Zhao;M. McCulloch;Guoqing Zhou;Fengjuan Xing
通讯作者：
Xian‐Hua Li;Jian-xin Zhao;M. McCulloch;Guoqing Zhou;Fengjuan Xing
影响因子：
3.5
作者：
D. Pearson;F. R. Boyd;Stephen E. Haggerty;J. Pasteris;S. Field;P. H. Nixon;N. Pokhilenko
通讯作者：
D. Pearson;F. R. Boyd;Stephen E. Haggerty;J. Pasteris;S. Field;P. H. Nixon;N. Pokhilenko
影响因子：
--
作者：
Yong‐Fei Zheng;Fu-guan Wu
通讯作者：
Yong‐Fei Zheng;Fu-guan Wu
影响因子：
2.1
作者：
Taijin Lu;Hua Chen;Zhi-li Qiu;Jian Zhang;W. Ran;Jie Ke;I. Sunagawa;R. Stern;T. Stachel
通讯作者：
Taijin Lu;Hua Chen;Zhi-li Qiu;Jian Zhang;W. Ran;Jie Ke;I. Sunagawa;R. Stern;T. Stachel
影响因子：
5.3
作者：
S. Boyd;C. Pillinger;H. Milledge;M. Seal
通讯作者：
S. Boyd;C. Pillinger;H. Milledge;M. Seal