Metal outgassing from Ambrym and Yasur volcanoes, Vanuatu

该项目将设法了解为什么瓦努阿图弧形火山向大气排放大量挥发性金属。将对Yasur和Ambrym火山喷发的岩石进行分析，以了解金属在硅酸盐熔体、硫化物相和挥发相之间的分配。这些研究将辅之以实地活动，以捕捉火山气体和气溶胶排放，其特点是其挥发性金属含量和形态。该项目将特别关注岩浆氯在挥发相析出的金属运输中的作用，并将自然数据与限制氯分配的实验进行比较。学生将对瓦努阿图亚苏尔和安布赖姆火山喷发的淬火岩石进行微观分析，例如使用扫描电子显微镜、电子探针和二次离子质谱仪对整个岩石、玻璃和硫化物中的主要、微量和挥发性元素进行量化。这名学生将在瓦努阿图进行实地考察，从亚苏尔和安布赖姆火山的火山口边缘获取火山气体和气溶胶样本，并将对其进行主要阴离子和阳离子(包括挥发性金属)以及硫同位素的分析。学生将利用这些观察结果来模拟金属在硅酸盐熔体、硫化物和水中流体之间的分配，以了解岩浆系统对fO2、压力和水中流体盐度等参数的敏感性，并深入了解火山对金属的加工和金属浓缩的机制。

This project will seek to understand why the volcanoes of the Vanuatu arc emit large fluxes of volatile metals to the atmosphere. Analysis of erupted rocks from Yasur and Ambrym volcanoes will be carried out in order to understand the partitioning of metals between silicate melt, sulphide phases and the exsolved volatile phase. These studies will be supplemented by a field campaign to capture volcanic gas and aerosol emissions, which will be characterised for their volatile metal content and speciation. In particular the project will focus on the role of magmatic chlorine in transporting metals in the exsolved volatile phase, and will compare natural data to experiments to constrain chlorine partitioning.The student will undertake microanalysis of erupted, quenched rocks from Yasur and Ambrym volcanoes, Vanuatu, e.g. using scanning electron microscopy, electron probe and secondary ion mass spectrometry to quantify major, trace and volatile elements in whole rocks, glasses and sulphides. The student will undertake fieldwork in Vanuatu to acquire samples of volcanic gases and aerosols from the crater rim at Yasur and Ambrym volcanoes, and will analyse them for major anions and cations (including the volatile metals), as well as for sulphur isotopes. The student will use these observations to model metal partitioning between silicate melt, sulphide and aqueous fluid to understand the sensitivities of the magmatic system with respect to parameters such as fO2, pressure and aqueous fluid salinity and produce insights into metal processing by volcanoes and the mechanisms of metal enrichment.