The behaviour of metals in magmatic-hydrothermal systems

了解岩浆-热液系统中金属的行为是破译许多类型矿床起源的关键。由于激光烧蚀诱导等离子体质谱（LA-ICP-MS）对矿物、流体包裹体和熔体包裹体中的金属进行分析的发展，这种认识在过去几年中得到了极大的改善。拟议的研究将利用该技术研究“稀有金属”（Ta-Nb-Sn-W-Mo）和贵金属（Pt-Pd-Au）矿床。随着电子产品和特种合金新用途的开发，稀有金属变得越来越重要，而且由于价格高昂，人们对贵金属的兴趣继续浓厚。为了改进勘探模式，有必要更好地了解集中这些元素的过程。这将通过实地调查来完成，在那里，矿石金属的丰度将在流体和熔融包裹体中确定。根据这些数据，将评价岩浆作用与热液作用的相对重要性。实地研究还将审查特征元素是否集中在关键矿物中。研究指示矿物与成矿作用的时空关系，建立矿床成因模型，评价指示矿物在热液矿床勘查中的作用。还将进行补充实验研究。这些包括确定Ta的扩散率和花岗岩熔体中钽矿物的溶解度，以及使用合成流体包裹体研究元素分配，特别是Au-As-Sb-Mo-W，在不混溶流体的汽相和液相之间。

Understanding the behaviour of metals in magmatic-hydrothermal systems is the key to deciphering the origin of many types of ore deposits. This understanding has improved dramatically in the last few years because of the development of laser ablation induced couple plasma mass spectrometry (LA-ICP-MS) analyses of metals in minerals, fluid inclusions and melts inclusions. The proposed research will take advantage of this technique to study 'rare-metal' (Ta-Nb-Sn-W-Mo) and precious metal (Pt-Pd-Au) ore deposits. The rare-metals are increasingly more important as new uses in electronics and specialty alloys are developed, and because of high prices, the interest in precious metals continues to be strong. It is necessary to better understand of the processes that concentrate these elements in order to improve exploration models. This will be accomplished by field investigations, where the abundances of the ore metals will be determined in fluid and melt inclusions. From these data the relative importance of magmatic versus hydrothermal processes will be evaluated. The field studies will also examine whether characteristic elements are concentrated in key minerals. The spatial and temporal relationships between these indicator minerals and mineralization will be characterized and applied to generating genetic models of ore deposits, and evaluating the use of indicator minerals to exploration of hydrothermal ore deposits. Complementary experimental studies will also be conducted. These include determining the diffusivity of Ta and solubility of tantalum minerals in granitic melts, and the use of synthetic fluid inclusions to study element partitioning, notably Au-As-Sb-Mo-W, between vapour and liquid phases of immiscible fluids.