| 应用稳定同位素示踪琥珀的产地 |
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| 引用本文： | 王雅玫,牛盼,谢璐华.应用稳定同位素示踪琥珀的产地[J].地质科学译丛,2013(3):9-17. |
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| 作者姓名： | 王雅玫 牛盼 谢璐华 |
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| 作者单位： | [1]中国地质大学珠宝学院,湖北武汉430074 [2]中国科学院广州地球化学研究所,广东广州510640 |
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| 摘 要： | 利用稳定同位素比值质谱仪（IRMS）对波罗的海琥珀、多米尼加琥珀、墨西哥琥珀、缅甸琥珀及不同产地的柯巴树脂的13C,D,18O稳定同位素进行了高精度测定.研究结果表明：（1）不同产地琥珀的δ13C值分布在一个较为稳定的范围内,缅甸琥珀δ13C=-19.38‰～-22.90‰,平均值为-21.15‰；波罗的海琥珀δ13C=-22.76‰～-25.76‰,平均值为-24.35‰;多米尼加琥珀δ13C=-23.57‰～-26.63‰,平均值为-24.99‰,且均值无交叉；（2）不同产地琥珀的δ13C值与琥珀形成的地质时代存在较好的线性关系.具体表征为随着天然树脂石化地质年代（琥珀化程度）的增加,13C值有规律地增大,据此可推断不同产地琥珀成熟度由高到低的相对顺序为缅甸＞波罗的海＞多米尼加、墨西哥；（3）柯巴树脂的δ13C值为-26.82‰～-29.94‰,平均为-28.55‰,比琥珀的明显贫δ13C,依据实验测试统计数据,推荐参考临界值为-27.00‰（＋0.18,-3.00）,这为界定琥珀与柯巴树脂提供了稳定同位素依据；（4）缅甸琥珀δD=-195.90‰～-244.40‰,平均为-226.00‰；波罗的海琥珀δD=-235.90‰～-270.10‰,平均为-25δ.80‰；多米尼加琥珀δD=-202.80‰～239.40‰,平均为-219.90‰；墨西哥琥珀δD=-218.90‰.不同产地琥珀中δD的同位素变异反映了环境水（大气降水）与古纬度之间的变化规律,即随着琥珀产地古纬度的增加,δD逐渐减小；（5）不同产地琥珀在13C-18O,D-18O同位素之间及13C,D,18O同位素在二维图解、三维空间中具有很好的分区性,表明碳、氢、氧稳定同位素综合分析可以示踪琥珀的产地信息.
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| 关 键 词： | 琥珀 柯巴 产地 稳定同位素 示踪 |
Stable Isotopes Tracing of Origin of Ambers |
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| Authors: | WANG Ya-mei NIU Pan XIE Lu-hua |
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| Institution: | 1. Gemmological Institute, China University of Geosciences, Wuhan 430074, China ; 2. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China) |
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| Abstract: | This paper analyzed C, H and O isotopes of amber from Baltic, Dominica, Mexico, Burma, and copals with Stable Isotope Ratio Mass Spectrography （CRMS）. First- ly, 313C of ambers ranges between --19.38‰ and --25.76‰. 313C of Burman ambers ranges between -- 19.38‰ and -- 22.90‰ with an average of -- 21.15 ‰. δ13 C of Baltic ambers ranges be- tween --22.76‰ and --25.76‰ with an average of --24.35‰, and 313C of Dominican ambers ran- ges between --23.57‰ and --26.63‰ with an average of --24.99‰. Average C isotopes of am- bers from those areas are different. Secondly, there is a good linear relation between 313C of ambers and their formation ages. With the increase in geological ages of natural ambers, 13C of ambers in- creases regularly. It is thus suggested that maturity degree of ambers （from high to low） isthe Burman amber, Baltic amber, Dominican and Maxican amber. Thirdly, δ13C of copals ranges between --26.82‰ and --29.94‰ with an average of --28.55‰. Based on data of experimental analyses, it is suggested that boundary value between amber and copal is --27.00‰ （＋0.18,--3.00） ,which may provide an isotopic evidence to distinguish between amber and copal. Fourthly, δD of Burman ambers ranges between --195.90‰ and --244.40‰ with an average of --222.59‰. δD of Baltic ambers ranges between --235.90%o and 268.60‰ with an average of --253.46‰. δD of Dominican ambers ranges between --203.30%o and --228.50%o with an average of --219.05‰, and that of Mexican ambers is --218.90‰. Change in δD of ambers is closely re- lated with latitude of amber formation. That is, with the increase of latitude, δD gradually decrea ses. Fifthly, two-dimensional space of 13C-18O isotopes and D--18O isotopes, and three-dimen sional space 13C, D, 18 O isotopes of ambers vary from different producing areas. It is thus sugges- ted that combinations of C, H and O isotopes of ambers can trace producing areas. |
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| Keywords: | amber copal producing area stable isotope tracing |
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