Abstract Rare-earth elements play a crucial role in modern technologies and are necessary for a transition to a green economy. Potentially economic deposits of these elements are typically hosted in minerals such as monazite, bastnasite, and eudialyte (a complex Na-Ca-Fe-Zr silicate mineral with Cl), making these prime targets for geological research. Globally, rare-earth mineral deposits commonly show evidence of polyphase development and mineralisation processes, which need to be better understood to improve exploration strategies. The Norra Karr alkaline complex (Sweden) contains a globally significant deposit of rare-earth elements, hosted in the mineral eudialyte. In this study, we focussed on eudialyte crystals in undeformed, cross-cutting pegmatoid veins from Norra Karr. In order to determine their age, we refined an established micromilling method to enable sampling of minerals rich in rare-earth elements for precise analysis of major and trace elements, Nd isotope ratios, and Sm-Nd geochronology down to a scale of

中文翻译：

---

在变质叠印过程中通过低温部分熔化对稀土元素矿床的改性：Norra Kärr 碱性复合物，瑞典南部

摘要 稀土元素在现代技术中起着至关重要的作用，是向绿色经济过渡所必需的。这些元素的潜在经济矿床通常存在于诸如独居石、氟碳铈矿和 eudialyte（一种复杂的 Na-Ca-Fe-Zr 硅酸盐矿物与 Cl）等矿物中，使这些成为地质研究的主要目标。在全球范围内，稀土矿床通常显示出多相开发和成矿过程的证据，需要更好地了解这些以改进勘探策略。Norra Karr 碱性复合物（瑞典）包含全球重要的稀土元素矿床，位于矿物 eudialyte 中。在这项研究中，我们专注于来自 Norra Karr 的未变形的横切伟晶岩脉中的 eudialyte 晶体。为了确定他们的年龄，