石盐中单个流体包裹体LA-ICP-MS测试方法研究

发布时间：2018-04-29 01:31

本文选题：激光剥蚀 + ICP-MS　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：流体包裹体是矿物晶体在生长过程中捕获周围的成矿流体而形成的,因此这些被捕获的流体包裹体完好的保存了矿物生长过程中的各种地球化学信息,所以对于流体包裹体的认识与研究对于地质行业的发展有着特殊的意义。激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)技术具有分析速度快、灵敏度高、空间分辨率好、受样品尺寸与性状影响小、以及多元素同时测定且能够提供同位素比值信息等一系列优势,因此可用于定量测定单个流体包裹体中常量和微量元素。采用LA-ICP-MS技术对单个流体包裹体成分进行分析,已经成为近年来流体包裹体研究的热点之一。然而,不同于一般固体矿物已经建立相对完善且系统的分析方法,流体包裹体由于剥蚀过程中所具有的特性以及自身的复杂性,针对单个流体包裹体的LA-ICP-MS分析方法还在探索中。本文对单体流体包裹体激光剥蚀ICP-MS的分析方法进行研究。通过配置的以饱和Na Cl溶液为基体的系列多元素标准溶液,填充至纯石英毛细管中,制成人工流体包裹体。对所配制的毛细管人工流体包裹体进行分析,除碘元素外,其它元素分析结果均表现出良好的精密度。直接以玻璃标样NIST610为外标,Na元素为内标,对毛细管人工流体包裹体(其中Na的含量采用饱和Na Cl溶液理论值)进行测定,其计算结果与所配制标准溶液理论值的相对误差约为+60%,可能是饱和Na Cl溶液在激光剥蚀过程中Na的析出所致。这表明直接以玻璃标样作为外标对流体包裹体进行校正分析存在较大的系统误差。若以Ca或Mg元素作为过渡内标,用玻璃标样NIST610对毛细管人工标样中的Na引入校正因子,然后以玻璃标样作为外标,Na元素作为内标元素,通过外标结合内标的校准方法,对毛细管人工包裹体进行校正分析,各金属元素的计算结果与配置理论值的相对误差均在9%以内。使用该方法对取自青海省察尔汗盐湖的石盐中流体包裹体样品进行分析计算,将计算结果与以直接以毛细管人工流体包裹体为外标的计算结果相比较,结果高度吻合。由此表明,所建立的单个流体包裹体LA-ICP-MS原位分析校准方法是可行且较准确的。本方法极大减少标准溶液配制中的繁琐工序,并有利于提高最终分析结果的准确性。
[Abstract]:Fluid inclusions are formed by capturing the surrounding ore-forming fluids during the growth of mineral crystals, so these trapped fluid inclusions have preserved all kinds of geochemical information in the process of mineral growth. Therefore, the understanding and research of fluid inclusions is of special significance to the development of geological industry. Laser denudation inductively coupled plasma mass spectrometry (LICP-MS) technique has a series of advantages, such as high analytical speed, high sensitivity, good spatial resolution, little influence by sample size and character, and the ability of simultaneous determination of multiple elements and the ability to provide isotope ratio information. Therefore, it can be used for quantitative determination of constants and trace elements in single fluid inclusions. The analysis of single fluid inclusions by LA-ICP-MS technique has become one of the hotspots in fluid inclusions research in recent years. However, unlike the relatively perfect and systematic analysis methods for solid minerals, the LA-ICP-MS analysis method for individual fluid inclusions is still being explored because of the characteristics and complexity of the denudation process. In this paper, the analytical method of laser denudation ICP-MS for single fluid inclusions is studied. Artificial fluid inclusions were prepared by filling a series of multielement standard solutions with saturated NaCl solution into pure quartz capillary. The capillary artificial fluid inclusions were analyzed and the analytical results of other elements except iodine showed good precision. The capillary fluid inclusions were directly determined with glass standard NIST610 as external standard and Na as internal standard, in which the content of Na was determined by saturated NaCl solution theory. The relative error between the calculated results and the theoretical value of the prepared standard solution is about 60, which may be due to the precipitation of Na in saturated NaCl solution during laser denudation. This indicates that there is a large systematic error in the correction and analysis of fluid inclusions directly using glass standard samples as external standard. If Ca or mg is used as the transitional internal standard, the calibration factor of Na in the capillary artificial standard is introduced by glass standard NIST610, then the glass standard sample is used as the external standard Na element as the internal standard element, and the calibration method of external standard combined with internal standard is adopted. The correction and analysis of capillary artificial inclusions show that the relative error between the calculated results of each metal element and the collocation theory is less than 9%. This method is used to analyze and calculate the fluid inclusions in the rock salt from Chaerhan Salt Lake in Qinghai Province. The calculated results are in good agreement with those calculated directly using the capillary artificial fluid inclusions as the external standard. It is shown that the calibration method for LA-ICP-MS in situ analysis of single fluid inclusions is feasible and accurate. This method greatly reduces the tedious procedure in the preparation of standard solution and improves the accuracy of the final analysis results.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P624

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