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激光剥蚀电感耦合等离子体质谱(LA-ICP-MS),由于其原位、实时、低检测限、高空间分辨率等优点,在矿物原位微量元素分析方面具有独特的优势。磁铁矿作为多种矿床和岩石中的常见矿物,其化学组成一直是国内外学者关注的焦点。而大量的研究表明,在磁铁矿LA-ICP-MS分析过程中,基体效应不明显,一般采用富铁硅酸盐玻璃作为标样,就能够取得较为准确的结果。因此近年来磁铁矿原位微量元素研究进展迅速,并在反演成岩成矿条件、辅助判别矿床类型和间接指导找矿勘探等方面显示出广泛的应用前景。通过总结25个不同类型岩浆和热液矿床中磁铁矿微量元素数据,与前人在矿床类型判别上的研究进行了一定的对比,发现常用的磁铁矿判别图解可以用来区分多种不同类型的矿床,但是已经划分出的分类边界可能需要进一步细化和严格验证,并且事先仔细的岩相学观察是数据解释的重要基础。另外,通过磁铁矿微量元素分配对岩浆和热液过程一系列复杂物理化学条件(熔/流体成分、温度、冷却速率、压力、氧逸度、硫逸度和二氧化硅活度等)的响应进行了一定探讨。在岩浆阶段,磁铁矿成分与熔体组成及分异演化密切相关;而热液阶段,流体性质的变化也会显著改变磁铁矿的化学成分。并且后期流体的改造或者磁铁矿的亚固相再平衡作用会对磁铁矿的成因鉴别产生严重干扰。综述了近年来LA-ICP-MS在磁铁矿微量元素分析方面的发展以及在矿床学领域的重要应用,以期对成矿作用和成矿过程研究提供新的思路和方向。
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has its unique advantages in in situ trace element analysis because of its advantages of in-situ, real-time, low detection limits and high spatial resolution. Magnetite, as a common mineral in many deposits and rocks, has always been the focus of attention both at home and abroad. However, a large number of studies have shown that the substrate effect is not obvious during the LA-ICP-MS analysis of magnetite. Generally, ferrous silicate glass is used as a standard sample to obtain more accurate results. Therefore, in recent years, the magnetite in-situ trace elements have been developed rapidly and have shown broad application prospects in the aspects of inversion of diagenetic mineralization conditions, aiding in the identification of deposit types and indirectly guiding prospecting exploration. By summarizing the microcalorimetric data of magnetite in 25 different types of magmatic and hydrothermal deposits, some contrastive studies have been done with the previous studies on the type of deposit, and the commonly used magnetite discriminating diagrams can be used to distinguish between different kinds of magnetite Types of deposits, the classified boundaries of the classification may require further refinement and rigorous verification, and careful petrographic observation is an important basis for data interpretation. In addition, a series of complicated physico-chemical conditions (melt / fluid composition, temperature, cooling rate, pressure, oxygen fugacity, sulfur fugacity and silica activity, etc.) of magma and hydrothermal processes Response to a certain discussion. In the magma stage, the composition of magnetite is closely related to the composition and evolution of melt. In the hydrothermal stage, the change of fluid properties also significantly changes the chemical composition of magnetite. And the late fluid modification or the subsolidification of magnetite rebalancing will cause serious interference to the identification of magnetite. In this paper, the development of LA-ICP-MS in the trace element analysis of magnetite and its important applications in the field of mineralogy are reviewed in this paper. The purpose is to provide new ideas and directions for the study of mineralization and metallogeny.