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

点击翻译按钮获取中文摘要

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.