Potential garnet reference materials for LA-ICPMS in-situ U-Pb isotope analysis

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Garnet is present in diverse magmatic, metamorphic, and metasomatic rocks and has an extensive pressure-temperature (P-T) stability field. Due to these characteristics, garnet is central to various areas of research in geosciences, including geochronology. Traditionally, garnet has been dated by means of Lu-Hf and/or Sm-Nd isochrons through time-consuming and tedious isotope dilution techniques. Recent instrumental advances and technical developments in the field of laser-ablation ICPMS, have led to the appearance of U-Pb dating of garnet by LA-ICPMS as a state-of-the-art technique in the field of Geochronology, with rapid data acquisition and processing, high spatial resolution, and relatively low costs. The growing number of recent studies hints at the immense potential of this technique. However, this technique is still in its infancy and one of the major obstacles to its widespread is the limited availability of garnet reference materials, which are essential for U-Pb analytical techniques using laser probes. During the last years, the applicant and his collaborators have studied several gem-quality garnet to test their suitability to become a reference material for U-Pb analysis. Preliminary data has yielded encouraging results in three of the studied localities. The objective of the project is to perform a complete geochemical characterization of those localities over a larger number of crystals before establishing them as reliable reference material for U-Pb dating. The analyses will be done by LA-ICPMS and TIMS techniques.