Experimental constraints on the behaviour of highly siderophile elements during planetary differentiation

行星分化过程中高亲铁元素行为的实验限制

• 批准号: 194228-2011
• 负责人: Brenan, James
• 金额: $ 2.44万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=593691
• 关键词: Experimental; constraints; behaviour; highly; siderophile

The highly siderophile, or iron-loving, elements (HSE) include the more familiar precious metals (platinum, palladium, rhodium and gold) as well as exotic varieties (rhenium, osmium, ruthenium and iridium). They are all useful to society, owing to exceptional thermal, surface and electronic properties. The HSE are also of value to geologists, as they are unique in their tendency to avoid oxygen, and bond to sulfur, as well as other "sulfur-like" elements, and iron. The HSE are therefore sensitive to the processes by which planets separate into a metallic core, mantle and crust. My research program involves laboratory simulation of these processes, with a specific focus on determining how the HSE get concentrated above normal background levels; be it by iron metal, other minerals, or unusual iron-sulfur (sulfide) melts. A major focus of the planned research will be to assess the efficiency of HSE extraction from magma by sulfide melt, and by compounds of the "sulfur-like" metals arsenic, bismuth, tellurium and selenium. This information helps us to understand how the HSE become concentrated by these elements in crustal mineral deposits. Knowledge of the sulfide scavenging capacity also makes it easier to inventory the HSE content of other planets from measurements of their surface lavas, whose sulfide has been removed at depth. In addition, we will determine the origin of some of the unusual behaviours of platinum, such as why it is so abundant in the Earth's mantle (when it should all be in the core) and why some magmas contain far more platinum than expected. We also plan to branch out into an emerging research area which deals with subtle variations in the composition of iron itself, and simulate the processes by which this may occur. In sum, this work seeks to provide the essential information for using the HSE to understand how planets form and evolve. Information gained from this research is also of value to the exploration and mining industry, as it provides information on how these elements may be concentrated to economic levels, and in what mineral forms they may occur.

高度亲铁的元素(HSE)包括更常见的贵金属(铂、钯、铑和金)以及稀有品种(Re、Os、Ru和Ir)。它们都对社会有用，因为它们具有特殊的热、表面和电子性质。HSE对地质学家来说也很有价值，因为它们有避免氧气的独特倾向，并与硫以及其他类似硫的元素和铁结合在一起。因此，HSE对行星分裂成金属核、地幔和地壳的过程很敏感。我的研究计划涉及对这些过程的实验室模拟，重点是确定HSE是如何在正常背景水平上浓缩的；无论是通过铁金属、其他矿物还是不寻常的铁-硫(硫化物)熔体。计划中的研究的一个主要重点将是评估通过硫化物熔融以及通过“类硫”金属砷、铋、碲和硒的化合物从岩浆中提取HSE的效率。这些信息有助于我们理解HSE是如何被这些元素集中在地壳矿床中的。对硫化物清除能力的了解也使得通过测量其他行星表面熔岩的HSE含量变得更容易，因为这些熔岩的硫化物已经在深处被清除。此外，我们将确定铂的一些不寻常行为的起源，例如为什么它在地幔中如此丰富(而它应该都在地核中)，以及为什么一些岩浆含有比预期多得多的铂。我们还计划扩展到一个新兴的研究领域，研究铁成分本身的微妙变化，并模拟可能发生这种变化的过程。总而言之，这项工作旨在为利用HSE了解行星的形成和演化提供必要的信息。从这项研究中获得的信息对勘探和采矿业也很有价值，因为它提供了关于这些元素如何集中到经济层面以及它们可能以何种矿物形式出现的信息。