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

钛铁矿 (FeTiO3) 的 LA-ICPMS 原位 U-Pb 定年

• 批准号: 492716706
• 负责人: Dr. Leo Jakob Millonig, since 11/2021
• 金额: --
• 依托单位: Abteilung Petrologie und Geochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2021
• 资助国家: 德国
• 起止时间: 2020-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/492716706?language=en
• 关键词: LA; ICPMS; situ; Pb; dating

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.

LA-ICPMS U-Pb定年是地球科学中最受欢迎和最成功的同位素技术之一，由于其高空间分辨率，良好的精度，快速和相对经济实惠，可以限制地质过程的时间和速率。因此，对金红石、磷灰石或钛铁矿等副矿物的年代学研究数量迅速增加，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调查。 然而，一些研究已经表明，钛铁矿可以在其晶格中容纳显著量的Zr，并且其分解可以导致形成第二相，例如斜锆石、斜锆石、锆英石和锆石。这些富Zr矿物由于其晶格中U的优先结合而经常用于U-Pb测年。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的过程中，对少数钛铁矿晶体进行了分析，以评估它们是否适合U-Pb定年，从而获得了成功。拟议项目的目的是通过LA-ICPMS对来自四个地点和岩性的样品进行钛铁矿的原位U-Pb定年，通过分析其他矿物或同位素系统已经知道了这些样品的地质年代学。设想的研究成果将提供一个新的地质年代学工具，适用于广泛的地质年代学研究问题，由于钛铁矿在各种岩性的普遍存在。我们认为，将U-Pb年龄与岩石学演化相结合，将大大提高对钛铁矿成因和演化的认识。