Dating heavy minerals in European rivers: What do they record?

Heavy minerals are essential for reconstructing provenance, paleogeography, and the evolution of continental crust, as well as for understanding petrological and tectonic processes. Moreover, analysing heavy minerals from modern rivers can be a more efficient way to assess the diversity of rock types exposed in a region than direct sampling of individual outcrops. Among these heavy minerals, detrital zircon has been extensively studied due to its robustness and suitability for U-Pb geochronology, providing critical age information on source rocks. However, the detrital zircon record in European rivers often does not quantitatively reflect the contributing drainage areas. This discrepancy is largely due to two factors: sediment recycling and the highly variable zircon fertility of different source rocks. To overcome these limitations, we expanded our analysis to include other heavy minerals from European river sediments. We focused on minerals that are both datable by the U-Pb method and less affected by recycling, such as titanite and apatite, as well as those found in zircon-poor lithologies, like rutile from mafic and metamorphic rocks. Our findings show that the U-Pb record of detrital rutile is similarly influenced by recycling, but in the case of the Variscan Orogeny, it records earlier events than zircon. In contrast, titanite, largely first-cycle in origin, best reflects the Alpidic Orogeny, an event that is nearly invisible in the detrital zircon and rutile records. Dating detrital apatite in combination with trace element analysis, is a useful tool for distinguishing between different geological processes, especially within the Variscan Orogeny.