In this study, we discuss potential problems connected with using geochronological data from foreland basins to unravel exhumation histories of the hinterland. In particular, we compare the results of a provenance analysis solely based on zircon fission-track ages from the foreland basin with a multi-method approach based on (i) the aforementioned zircon fission-track data, (ii) Nd isotope ratios of detrital epidote, and (iii) sediment accumulation rates in the foreland basins. For the example of the Central European Alps, we demonstrate that the multi-method approach can lead to highly different interpretations in terms of hinterland exhumation and geodynamic evolution. This is due to the fact that fission-track dating on detrital zircons alone only monitors the exhumation and erosion of zircon-containing lithologies and therefore only of restricted areas of the hinterland while the combination with Nd isotope ratios on detrital epidote also includes the erosion of zircon-free or -poor units such as basic magmatic rocks. A comparison of zircon fission-track and epidote Nd data with the sediment accumulation curve shows whether hinterland exhumation was predominantly caused by tectonic or by erosional denudation. Furthermore, we discuss some problems that may arise from using geochronological data from foreland basins to assess the maturity of a mountain belt in the hinterland. Applied to the Central Alps, our combined approach shows that the metamorphic core became exposed simultaneously over large areas by one sudden pulse of exhumation between 21 and 20 Ma. The main trigger for that exhumation event was tectonic denudation which is consistent with a geodynamic setting of large-scale extension. The Central Alps did not achieve exhumational steady-state conditions before 14 Ma.

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Terranes of different geotectonic settings accreted during Paleozoic time to form a consolidated crust by the end of the Variscan orogenic cycle. An ensimatic island arc, which rested upon back-arc oceanic crust and is now preserved in the Penninic unit of the Tauern window, was active in early Paleozoic time. Accretion of ensialic magmatic arcs and (back-arc?) oceanic crust occurred in Ordovician time to form a composite terrane in the Austroalpine unit. Limited radiometric information from zircon provides evidence for the existence of Precambrian cores. An ocean is inferred to have closed by about the early Carboniferous period, thus forming an important ophiolitic suture. Accretion of oceanic terranes and dispersion of the active continental margin by inferred large-scale wrench faulting accompanied this process.