Investigation of O-isotopes in Na-Al-rich chondrules and Ca,Al-rich inclusions from ordinary chondrites

为了理解为什么我们的太阳系是今天的样子，我们需要破译自45.67亿年前形成以来形成其组成部分的过程。陨石对于研究这些过程至关重要，因为它们携带着宇宙信息和第一批粒子的历史，这些粒子是在物质开始合并成更大的行星体之前出现的。因此，不仅要研究大块陨石，还要研究它们的单个组成部分，这是获得我们年轻的太阳系演化信息的绝佳途径。球粒陨石由不同的成分组成，如球粒（球粒陨石得名的熔融液滴）和所谓的难熔包裹体，如富钙、富铝包裹体。这些富含钙、铝的包裹体被认为是最古老的粒子，标志着我们太阳系的开始~ 45.67亿年前，它们可能是上述球粒的前体物质。以前关于富钙、富铝包裹体如何形成的模型认为，它们在非常短的时间内（<2万年）在年轻的太阳附近形成，然后不均匀地分布在整个太阳盘中。在博士论文中，申请人通过研究一种被称为富钠铝球粒的球粒，发现除了富钙、富铝的内含物外，还可能存在一种未知类型的耐火材料作为球粒的前体。这种未知的耐火材料在矿物学上与富钙、富铝包裹体相似，但在钛同位素组成上有所不同。因此，耐火成分（富Ca、富al包裹体和这种未知物质）必须在至少两个同位素不同的区域形成；这一暗示挑战了当前单一形成区域的耐火材料模型。该项目的目的是通过首次调查普通球粒陨石中罕见的富含na - al的球粒中的o同位素，来弄清这些区域的确切位置。由于早期太阳系的每个区域都有自己的o同位素指纹，这将使我们能够得出关于这种未知的难熔球粒前体物质形成的结论。这个项目还将帮助我们确定富钠铝球粒是在普通球粒陨石区域本身形成的，还是在吸积之前被运送到这个区域，就像人们认为的那样，富钙铝包裹体发生了这种情况。总的来说，研究太阳系中最早粒子的形成和分布是一个重要的跨学科兴趣，因此这个项目对于例如模拟我们年轻太阳系的演化将是重要的。

In order to understand why our solar system looks the way it does today, we need to decipher the processes that have shaped its components since their formation ~4,567 million years ago. Meteorites are essential for studying these processes, as they carry the cosmological information and history of the first particles that emerged before matter started coalescing into larger planetary bodies. Consequently, studying not only bulk meteorites but also their individual components is an excellent way to gain information about the evolution of our young solar system.Chondritic meteorites consist of different components such as chondrules (melt droplets that chondritic meteorites are named after) and so-called refractory inclusions such as Ca,Al-rich inclusions. These Ca,Al-rich inclusions are considered to be the oldest identified particles and mark the beginning of our solar system ~4,567 million years ago, and they may represent a precursor material for the above-mentioned chondrules. The previous model of how Ca,Al-rich inclusions formed states that they formed in a very short time (<20k years) near the young sun and were then unevenly distributed throughout the solar disk.In his doctoral thesis, the applicant revealed, through studying a type of chondrule called Na-Al-rich chondrules, that in addition to Ca,Al-rich inclusions, an unknown type of refractory material may exist as a precursor for chondrules. This unknown refractory material is similar in mineralogy to Ca,Al-rich inclusions but differs in its composition of Ti-isotopes. As a result, refractory components (Ca,Al-rich inclusions and this unknown material) must have formed in at least two isotopically different regions; this implication challenges the current model of a single formation region for refractory materials.The aim of this project is to clarify where exactly these regions were situated by investigating, for the first time, the O-isotopes in the rare group of Na-Al-rich chondrules in ordinary chondrites. Since each region in the early solar system has its own O-isotopic fingerprint, this will allow us to draw conclusions about where this unknown refractory chondrule precursor material formed.This project will also help us determine whether Na-Al-rich chondrules actually formed in the ordinary chondrite region itself or were transported to this region before accretion, as it thought to have happened for Ca,Al-rich inclusions. In general, studying the formation and distribution of the earliest particles in our solar system is of significant interdisciplinary interest, and this project will thus be important for e.g. model the evolution of our young solar system.