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Loess–palaeosol sequences (LPSs) are key archives for the reconstruction of Quaternary environmental conditions, but there is a lack of investigated records from the southern Upper Rhine Graben (southwestern Germany). To close this gap, a LPS at Bahlingen-Schönenberg was investigated at high resolution using a multi-method approach. Infrared stimulated luminescence screening reveals a major hiatus in the lower part of the LPS that according to luminescence dating is older than marine isotope stage (MIS) 4. The section above the hiatus formed by quasi-continuous loess sedimentation between ca. 34 and 27 ka, interrupted by phases of weak reductive pedogenesis. The fact that this pedogenesis is much weaker compared to corresponding horizons in the more northerly part of the Upper Rhine Graben could be due to regionally drier conditions caused by a different atmospheric circulation pattern at the time of deposition. Our results reinforce earlier notions that the major environmental shifts leading into the Last Glacial Maximum (LGM) of southern Central Europe significantly predate the transition of MIS 3 to 2 (ca. 29 ka). In particular, the last massive phase of loess accumulation started several thousand years prior to the arrival of glaciers in the foreland of the Alps, which raises questions regarding the source and transport paths of the dust. It is also noted that no loess dating to the LGM or the time thereafter was observed due to either a lack of deposition or later erosion. Kurzfassung: Löss-Paläoboden Sequenzen (LPS) sind Schlüsselarchive für die Rekonstruktion von quartären Umweltbedingungen, aber es mangelt an der Untersuchung solcher Abfolgen aus dem südlichen Oberrheingraben. Um diese Lücke zu schließen, wurde eine LPS bei Bahlingen-Schönenberg mit einem multimethodischen Ansatz hochauflösend untersucht. Die Untersuchung mit Infrarot Stimulierter Lumineszenz Screening zeigt einen Hiatus im unteren Teil der LPS, der laut Lumineszenzdatierungen älter ist als das Marine Isotopenstadium (MIS) 4. Der Abschnitt oberhalb des Hiatus bildete sich durch quasi-kontinuierliche Lössablagerung zwischen ca. 34 und 27 ka, unterbrochen von Phasen schwacher reduktiver Pedogenese. Da die Pedogenese im Vergleich zu entsprechenden Horizonten im nördlicheren Teil des Oberrheingrabens viel schwächer ausgeprägt ist, könnte dies auf regional trockenere Bedingungen zurückzuführen sein, verursacht durch ein anderes atmosphärisches Zirkulationsmuster zur Zeit der Ablagerung. Unsere Ergebnisse bestätigen frühere Annahmen, dass die großen Umweltveränderungen, die zum letzten glazialen Maximum (LGM) im südlichen Mitteleuropa führten, deutlich vor dem Übergang von MIS 3 zu 2 (ca. 29 ka) lagen. Insbesondere begann die letzte massive Phase der Lössakkumulation mehrere tausend Jahre vor der Ankunft der Gletscher im Alpenvorland, was Fragen zu den Quellen und Transportwegen des Staubs aufwirft. Es ist auch festzustellen, dass kein Löss aus dem LGM oder der Zeit danach gefunden wurde, entweder aufgrund fehlender Ablagerung oder späterer Erosion. [ABSTRACT FROM AUTHOR]

Rock surface dating, a relatively new approach within luminescence dating, determines when a rock surface was last exposed to sunlight by measuring the amount of latent OSL signal accumulated after burial. However, the potential and applicability of rock surface dating in glaciofluvial settings of the Alps has seen very limited application so far (Rades et al., 2018). Therefore, different luminescence methods including rock surface dating have been applied in a unique setting at the Hartheim gravel pit in the southern Upper Rhine Graben to establish a chronological frame for distal glaciofluvial deposits. First, a detailed field study was conducted in order to gather a comprehensive understanding of the different sediment types present. Fine grain sand, cobbles, pebbles and matrix sediments embedded within large clasts were collected and analyzed using a combination of OSL and IRSL dating. Conventional OSL dating of fine sand quartz is considered as robust age control compared to the other sediment types. A substantial amount of luminescence measurement has been done on the sand lens and gravel matrix sediment collected from Hartheim. OSL ages range around from ca. 19 ka to 32 ka for the different sediment types. Feldspar IRSL has been measured using a MET-pIRIR protocol to avoid problems with fading. Furthermore, a detailed dosimetry study was conducted to measure the varying levels of radionuclide concentration within materials of different grain size, in order to obtain accurate depositional ages. Overall, the purpose of this research contributes to our existing knowledge in the field of luminescence dating by showing the potential and versatility of different luminescence methods in different sediment types and environments that provide an ideal framework for future studies in similar contexts. [ABSTRACT FROM AUTHOR]