Magmatic geochemistry of chalcophile and siderophile elements

亲硫和亲铁元素长期以来一直被认为是类地行星小规模和大规模分化过程的有价值的示踪剂，除了它们作为具有独特的热，表面和电子性质的元素的社会用途之外。 尽管它们在这方面很重要，但我们目前对这些元素的地球化学的了解大多是经验性的，并且具有相当大的不确定性。然而，详细了解它们的地球化学行为对于充分解释天然丰度数据和开发先进的矿床勘探模型至关重要。 在过去的五年里，我的研究重点是开发技术和实施实验，以更好地评估岩浆过程在控制这些元素的一个子集，即Re和铂族元素的行为中的作用。 在下一个供资周期，我计划扩大这项工作的范围，包括了解甚少的亲铜非金属和准金属铅，硒，碲，砷和锑，这些元素通常存在于微量到微量丰度水平的贱金属硫化物偏析，在某些情况下，可能是矿物中的主要阴离子，集中亲铁元素。 拟议的工作将特别侧重于这些元素在地壳和地幔内转移和集中的程度。 实验将利用多伦多大学的设施进行，使用模拟地球深处极端条件的机器和在高温下分离混合样品的新型离心装置。 这些实验的产物将使用最先进的分析技术进行表征，包括激光烧蚀ICP-MS和基于同步加速器的光谱学。

The chalcophile and siderophile elements have long been recognised as valuable tracers of the processes responsible for small- and large-scale differentiation of the terrestrial planets, in addition to their societal uses as elements with unique thermal, surface and electronic properties.  Despite their importance in this regard, much of our current knowledge of the geochemistry of these elements is empirical, and subject to considerable uncertainty. However, a detailed understanding of their geochemical behaviour is essential to fully interpret natural abundance data, and develop advanced models for ore exploration.  Over the past five years, my research has focused on developing techniques and implementing experiments to better assess the role of magmatic processes in controlling the behaviour of a subset of these elements, namely Re and the platinum group elements.  In the next funding cycle, I plan to expand the scope of this work to include the poorly understood chalcophile non-metals and metalloids Pb, Se, Te, As and Sb.  These are elements that are typically present at trace to minor abundance levels in base metal sulfide segregations, and in some cases may be the principal anion in minerals that concentrate the siderophile elements.  The proposed work will specifically focus on the extent to which these elements are transferred and concentrated within Earth's crust and mantle.  Experiments will be done using facilities at University of Toronto, employing machines that simulate the extreme conditions of the deep Earth, and a novel centrifuge device for separating mixed samples at high temperature.  The products of these experiments will be characterised using state-of-the-art analytical techniques, including laser ablation ICP-MS, and synchrotron-based spectroscopy.