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.

高度亲铁元素（HSE）包括更常见的贵金属（铂、钯、铑和金）以及外来品种（铼、锇、钌和铱）。由于具有卓越的热性能、表面性能和电子性能，它们对社会都有用。 HSE 对地质学家也很有价值，因为它们具有独特的避免氧并与硫以及其他“硫类”元素和铁结合的倾向。因此，HSE 对行星分离成金属核、地幔和地壳的过程非常敏感。我的研究项目涉及这些过程的实验室模拟，特别关注确定 HSE 如何集中到正常背景水平之上；可能是由铁金属、其他矿物或不寻常的铁硫（硫化物）熔体产生的。计划研究的一个主要重点将是评估通过硫化物熔体以及“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了解 HSE 如何被地壳矿床中的这些元素浓缩。了解硫化物清除能力还可以更容易地通过测量其他行星表面熔岩的 HSE 含量来清查其 HSE 含量，这些行星的硫化物已在深处被清除。此外，我们还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（当它应该全部在地核中时）以及为什么一些岩浆含有比预期更多的铂。我们还计划扩展到一个新兴的研究领域，该领域涉及铁本身成分的细微变化，并模拟可能发生这种情况的过程。总之，这项工作旨在提供使用 HSE 来了解行星如何形成和演化的基本信息。从这项研究中获得的信息对于勘探和采矿业也很有价值，因为它提供了有关这些元素如何集中到经济水平以及它们可能以什么矿物形式出现的信息。