Luminescence dating of large clast rock surfaces buried in glaciofluvial sediments of the southern Upper Rhine Graben.

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]