11/01/2024

Dr. Aratz Beranoaguirre

16:00 Uhr

Laser-ablation ICP-MS U-Pb dating has proven to be of great value for many geoscience disciplines. For a long time, this technique has primarily been used to date accessory minerals such as rutile, monazite, and especially zircon. Recently, this technique has been applied to rock-forming minerals with low U and high common-Pb concentrations such as garnet or carbonates.
Carbonate dating is the most developed field with a few tens of publications per year from an increasing number of different laboratories. The applications of carbonate dating are manifold and encompass, e.g., the dating of sedimentation or fossilization processes, which can be combined with stable or clumped isotopes studies, or structural studies that investigate calcite fibres and vein formation related to folds and thrusts.
In the case of garnet dating, two areas of research should be distinguished. Skarn garnet, with U concentrations of ca. 2 to 70 µg/g, has proven a fruitful target for U-Pb dating. In turn, garnet from igneous or metamorphic rocks, including metasomatic garnet from the subcontinental lithospheric mantle, is much more challenging due to abundant inclusions and/or extremely low U concentrations (usually <1 µg/g). However, recently developed methodologies overcome this issue of dating garnet with ca. 1 ng/g U and significantly widen the application of the U-Pb geochronometer in garnet.
Finally, dating mineralization-related minerals, like cassiterite, columbite, wolframite or scheelite is also an emerging field developed in the last couple of years. Providing a temporal framework for such minerals may give important insights into the understanding of the formation and evolution of the main ore bodies and thus guide exploration efforts on a local and regional scale.