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看起来会是今天的样子，我们需要破译自45.67亿年前太阳系形成以来塑造其组成部分的过程。陨石对于研究这些过程至关重要，因为它们携带着宇宙学信息和在物质开始聚合成更大的行星体之前出现的第一批粒子的历史。因此，不仅研究块状陨石，而且研究它们的个体成分，是获得我们年轻太阳系演化信息的极好途径。球粒陨石由不同的成分组成，如球粒陨石(球粒陨石以熔滴命名)和所谓的难熔包裹体，如富钙、铝的包裹体。这些富Ca、Al包裹体被认为是已发现的最古老的粒子，标志着我们的太阳系在45.67亿年前就开始了，它们可能是上述球粒陨石的先驱物质。先前关于富Ca、Al包裹体形成的模型指出，它们在年轻的太阳附近形成的时间非常短(约20k年)，然后不均匀地分布在整个太阳盘。在他的博士论文中，申请人通过研究一种被称为富Na-Al球粒的球粒陨石，揭示了除了Ca、Al富包裹体之外，可能还存在一种未知类型的耐火材料，作为球粒陨石的先驱。这种未知的耐火材料在矿物学上与富Ca、Al包裹体相似，但其钛同位素组成不同。因此，耐火组分(钙、富铝包裹体和这种未知物质)必须形成在至少两个同位素不同的区域；这意味着对目前耐火材料单一形成区域的模式提出了挑战。该项目的目的是通过首次研究普通球粒陨石中稀有的富Na-Al球粒陨石中的氧同位素，来澄清这些区域的确切位置。由于太阳系早期的每个区域都有自己的氧同位素指纹，这将使我们能够得出结论，这种未知的难熔球粒陨石前体物质是在哪里形成的。这个项目也将帮助我们确定富Na-Al球粒陨石实际上是在普通球粒陨石区域形成的，还是像人们认为的那样，在吸积之前被输送到这个区域，就像人们认为的那样，发生在富钙、铝的包裹体中。总体而言，研究太阳系中最早的粒子的形成和分布具有重大的跨学科意义，因此该项目将对例如模拟我们年轻太阳系的演化具有重要意义。

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.