LA-ICPMS in-situ U-Pb dating of Ilmenite (FeTiO3)

LA-ICPMS的U-Pb定年技术是地球科学中最流行和最成功的同位素技术之一，它具有高空间分辨率、高精度、快速和相对负担得起的优点，可以限制地质过程的时间和速率。因此，对附属矿物如金红石、磷灰石或钛矿等的地质年代学研究正在迅速增加，从而提高了对小规模过程的认识。在钛铁矿等其他矿物中使用这些技术的可能性几乎没有研究过。然而，一些研究表明，钛铁矿可以在其晶格中容纳大量的Zr，其破裂可导致二次相的形成，如坏辉石、硅钛石、锆石和锆石。这些富锆矿物通常用于U- pb定年，因为它们的晶格中优先结合了U。最近，在法兰克福同位素和元素研究中心（FIERCE）实验室开发新的地质年代学方法期间，对少量钛铁矿晶体进行了分析，以评估其对U-Pb定年的适用性，并取得了成功。拟议的项目旨在利用LA-ICPMS对来自四个地点和岩性的钛铁矿样品进行原位U-Pb测年，这些样品的地质年代学已经通过分析其他矿物或同位素系统而已知。由于钛铁矿在各种岩性中普遍存在，预期的研究结果将提供一种新的地质年代学工具，适用于广泛的地质年代学研究问题。我们认为，将U-Pb年龄整合到岩石学演化中，将大大提高对钛铁矿成因和演化的认识。

U-Pb dating by LA-ICPMS is one of the most popular and successful isotopic techniques available to the Earth Sciences to constrain timing and rates of geological processes thanks to its high spatial resolution, good precision, rapidity and relative affordability. As consequence, the number of geochronological studies in accessory minerals like rutile, apatite or titanite among others, are rapidly increasing, improving the knowledge of the small-scale processes. The possibility to use those techniques in other minerals like ilmenite is barely investigated. However, several studies have shown that ilmenite can accommodate significant amounts of Zr in its crystal lattice and its breakdown can lead to the formation of secondary phases such as baddeleyite, srilankite, zirconolite and zircon. These Zr-rich minerals are regularly used for U-Pb dating due to the preferential incorporation of U in their crystal lattice. Recently, during the development of new geochronological methods in the Frankfurt Isotope and Element Research Center (FIERCE) laboratory, few ilmenite crystals were analyzed to evaluate their suitability for U-Pb dating, resulting in a successful approach. The proposed project aims to accomplish in-situ U-Pb dating of ilmenite by LA-ICPMS in samples from four localities and lithologies, which geochronology is already known through the analysis of other minerals or isotope systems. The envisioned research outcome will provide a new geochronological tool that applies to a wide range of geochronological research questions, due to the ubiquity of ilmenite in various lithologies. We consider that integrating U-Pb ages into the petrologic evolution will considerably enhance the understanding of the origin and evolution of ilmenite.