Magmatic geochemistry of chalcophile and siderophile elements

亲铜元素和亲铁元素的岩浆地球化学

• 批准号: 194228-2006
• 负责人: Brenan, James
• 金额: $ 3.47万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=332512
• 关键词: Magmatic; geochemistry; chalcophile; siderophile; elements

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.

亲铜和亲铁元素一直被认为是有价值的示踪剂，除了它们作为具有独特的热、表面和电子特性的元素在社会上的用途外，还对类地行星的小型和大规模分化过程负责。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知识大多是经验的，而且存在相当大的不确定性。然而，详细了解它们的地球化学行为对于充分解释自然丰度数据和开发先进的矿石勘探模型至关重要。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子集（即Re和铂族元素）行为中的作用。在下一个资助周期中，我计划扩大这项工作的范围，包括尚不了解的亲铜非金属和类金属Pb、Se、Te、As和Sb。这些元素通常在贱金属硫化物分离中以微量到少量的丰度水平存在，在某些情况下可能是矿物中富集亲铁元素的主要阴离子。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。实验将使用多伦多大学的设备，使用模拟地球深处极端条件的机器，以及在高温下分离混合样品的新型离心机设备。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。