Detrital zircon geochronology and garnet geochemistry of sandstones from Cretaceous-Paleogene foreland basins in the Dinarides

Cretaceous-Paleogene foreland basins in the Dinarides formed as a consequence of convergence between Adriatic and European plate. These basins were filled by detritus composed of variable amount of carbonate and siliciclastic material, providing record of various units exposed during the initial stages of orogenesis. This study presents detrital zircon geochronology and garnet major-element geochemistry of sandstones from these basins, sampled from different stratigraphic levels from northwestern Croatia to Montenegro, covering almost the entire length of the Dinarides. Preliminary data point to a substantial difference between Lower Cretaceous and Upper Cretaceous-Paleocene sandstones, especially regarding detrital zircon age spectra. The most important dissimilarity is noticeable Permo-Triassic population in the Lower Cretaceous sandstones, completely absent or less pronounced in the Upper Cretaceous and Paleocene ones. The Upper Cretaceous and Paleocene sandstones display variability regarding proportion of Variscan and Cenerian, as well as Precambrian zircon populations. Composition of garnets points to derivation from low to medium grade metamorphic rocks. These new data provide basis for regional interpretation of Cretaceous-Paleogene foreland basins in the Dinarides, and insight into the temporal and spatial diversity of sediment sources during the initial stages of orogeny. The presented work is supported by the Croatian Science Foundation project SECret (HRZZ IPS-2023-02-2683).