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Planetary Origins and Development

行星起源与发展

基本信息

批准号：
ST/M001318/1
负责人：
Alex Halliday
金额：
$ 87.35万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FM001318%2F1
关键词：
Planetary Origins Development

项目摘要

The research in this proposal tries to answer questions about how our solar system and its reservoirs first formed. We are proposing to focus our efforts on the issue of how terrestrial planets acquired their metallic cores (the same cores that drive planetary magnetic fields). In the process we will also determine how the silicate Earth's budgets of metal loving elements like Ni originated. We will make comparisons between the differentiated planets and asteroids, Earth, Mars, Vesta and the angrite parent body on the one hand and the Moon on the other and use these data to better constrain lunar origins. We use a combination of isotopic measurements using mass spectrometry, and experimental simulation at high pressures and temperatures. We have isotopic evidence that metallic cores of planets started forming very early; within the first million years or so of the Solar System's earliest objects, calcium aluminium refractory inclusions. These cores formed from molten rock created from accretional energy and, initially, radioactive decay. As metallic cores form they partition a variety of elements into the dense segregating metallic liquids partially removing these elements from the residual silicate planet. The degree of depletion and the magnitude of any associated isotopic fractionation will depend on the conditions under which these cores formed, in particular the pressure, temperature, oxygen fugacity and sulphur content. Therefore, by measuring the isotopic compositions of primitive meteorites and comparing them with those of samples of the silicate and metal portions of asteroids, Mars, Earth and the Moon one can deduce the environment under which different planetary objects first developed. To quantify these environments it is necessary to calibrate the isotopic and chemical effects with experimental determinations. We will focus our attention on vanadium, chromium, nickel, molybdenum, tungsten and, if time permits, ruthenium.

这项提案中的研究试图回答有关太阳系及其储存库最初是如何形成的问题。我们建议把我们的努力集中在类地行星是如何获得它们的金属核（驱动行星磁场的相同核）的问题上。在这个过程中，我们还将确定地球上的硅酸盐是如何形成像Ni这样的亲金属元素的。我们将对不同的行星和小行星、地球、火星、灶神星和花岗岩母体以及月球进行比较，并利用这些数据更好地约束月球的起源。我们结合使用质谱法进行同位素测量，并在高压和高温下进行实验模拟。我们有同位素证据表明，行星的金属核很早就开始形成了；在太阳系最早的物体的最初100万年左右，钙铝难熔夹杂物。这些地核是由熔岩形成的，这些熔岩是由吸积能量和最初的放射性衰变形成的。随着金属核的形成，它们将各种元素分割成密集的分离金属液体，部分地将这些元素从残余的硅酸盐行星中移除。枯竭的程度和任何相关同位素分馏的大小将取决于这些岩心形成的条件，特别是压力、温度、氧逸度和硫含量。因此，通过测量原始陨石的同位素组成，并将其与小行星、火星、地球和月球的硅酸盐和金属部分的样品进行比较，可以推断出不同行星物体最初形成的环境。为了量化这些环境，有必要用实验测定来校准同位素和化学效应。我们将重点关注钒、铬、镍、钼、钨，如果时间允许，还将关注钌。