Methodological advances in luminescence dating in the context of Quaternary climate and tectonics within Upper Rhine Graben

From the Late Pleistocene to the Holocene, river dynamics in central Europe were profoundly shaped by hydro-climatic variations and human-induced factors. The Rhine River, as one of Europe’s largest and most dynamic fluvial systems, has been strongly influenced by these changes. Upper Rhine Graben (URG) is a part of the European Cenozoic Rift System and extends from Basel in the south to Frankfurt in the north. Acting as a long-term and large scale sediment sink for the Rhine River, the URG, along with its subsidence dynamics, has preserved a rich sedimentary archive documenting the history of Rhine floodplain evolution. Therefore, in light of ongoing climate change and the increasing human pressure, a deeper understanding of the long- and short-term depositional history of the URG is essential. However, the palaeodynamics of the Upper Rhine system remain poorly understood until today, primarily due to the absence of a detailed geochronological framework from this region. In particular, the coarse-grained stratigraphy and the lack of sediment exposure make it difficult to establish reliable chronological constraints in the central and southern URG. The central aim of this study is, therefore, to establish reliable chronological constraints from fluvial and distal glaciofluvial deposits from this region, which can provide valuable insights in disentangling the complex depositional history of this Quaternary graben fill and to reconstruct the evolving river dynamics of the Rhine, its tributaries and sub-tributaires. Over the past few decades, luminescence dating has become an emerging geochronological tool to determine the depositional ages of sediments. Despite significant methodological advancements, unavoidable challenges still remain associated with this dating method, which prevents determining ‘true’ depositional ages of sediments. Current study addresses these limitations by applying luminescence dating to a range of stratigraphic contexts within URG. Fine sand grains, gravel-rich matrix materials and clasts are collectively dated in this study and robust luminescence age constraints are established for distinct fluvial and distal glaciofluvial stratigraphic units in this region. In parallel, the study advances several methodological refinements, aiming to mitigate the effects of partial bleaching and anomalous fading, two critical challenges commonly associated with this dating method. Together, the findings of the study contribute to establish a reliable geochronological framework for URG and address luminescence methodological limitations, enhancing the accuracy of depositional age estimation using this technique.