Thanks to their high chemical and mechanical stability, their diffusion in all types of detrital sediments and their complex structural formula (XY₃Z₆(T₆O₁₈)(BO₃)₃V₃W), tourmalines have attracted strong interest in provenance studies since, from their chemical composition, it is possible to reconstruct the source rocks in ancient sediments. Dravite and schorl, belonging to the alkali subgroup 1, are the most abundant tourmaline species, and they have different Y-site compositions in the unit cell: dravite has more magnesium, while schorl has a higher iron content. For this reason, it is important to measure the Mg–Fe relative content in order to classify the analysed tourmalines in the dravite–schorl series. Raman spectroscopy is a suitable technique as it allows quick and easy measurements that provide chemical and structural information on tourmalines with a high spatial resolution, thus allowing analysis of small grains that could be found in sediments. In this work, we correlated the relative Mg–Fe content (x = Mg/(Mg + Fe)) in different tourmaline samples from the dravite–schorl series ( ) with variations in Raman spectrum parameters in order to find a model for quick tourmaline identification useful for provenance studies. The chemical compositions of the analysed tourmalines are obtained by scanning electron microscope coupled with energy-dispersive spectroscopy (SEM-EDS). Raman measurements with a portable spectrometer have also been performed in order to evaluate our results for in situ applications.

中文翻译：

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拉曼光谱研究透镁石系列电气石中的 Mg-Fe 含量

由于其高化学和机械稳定性、在所有类型碎屑沉积物中的扩散性以及复杂的结构式 (XY ₃ Z ₆ (T ₆ O ₁₈ )(BO ₃ ) ₃ V ₃ W)，电气石引起了人们对产地的浓厚兴趣研究人员认为，根据其化学成分，可以重建古代沉积物中的烃源岩。属于碱金属亚组 1 的电气石和 schorl 是最丰富的电气石种类，它们在晶胞中具有不同的 Y 位组成：钠镁石含有更多的镁，而 schorl 具有更高的铁含量。因此，测量 Mg-Fe 相对含量非常重要，以便对分析的电气石进行镁镁石-镁铁矿系列的分类。拉曼光谱是一种合适的技术，因为它可以快速、轻松地进行测量，以高空间分辨率提供电气石的化学和结构信息，从而可以分析沉积物中发现的小颗粒。在这项工作中，我们关联了镁镁铁矿系列中不同电气石样品中的相对镁铁含量 (x = Mg/(Mg + Fe))（ ）与拉曼光谱参数的变化，以便找到可用于来源研究的快速电气石识别模型。所分析的电气石的化学成分是通过扫描电子显微镜结合能量色散光谱（SEM-EDS）获得的。还使用便携式光谱仪进行拉曼测量，以评估我们的现场应用结果。