Work

Luminescence dating of alluvial sediments from the Quaternary fan–terrace sequence of the lower Bruche valley, Upper Rhine Graben, France

Year: 2025

Type: article

Abstract: Geochronological constraints on fluvial terraces provide valuable insights into channel migration and adjustment involved within actively meandering river systems. However, numerical age estimation of fluvial deposits using luminescence dating is often challenged by inherent methodological limitations. Pre-depositional partial bleaching of grains can lead to overestimation, while anomalous fading in feldspar grains often results in underestimation of the luminescence ages. The current study applies both optically stimulated luminescence and multi-elevated temperature post-infrared infrared stimulated luminescence dating to fine sand and sandy matrix deposits collected from three distinct fluvial terrace levels across the lower reach of the Bruche River, in the Upper Rhine Graben (URG, north-eastern France). To evaluate the extent of partial bleaching, modern alluvial sand from the active riverbed is analysed for residual luminescence signals. Additionally, fading rates are measured, and quartz and feldspar ages are compared to evaluate the effectiveness of the applied measurement protocol in targeting signals less susceptible to fading. Overall, our study provides (i) a methodological focus, highlighting the effect of partial bleaching and fading on age estimation, and (ii) new insights into landscape evolution of the lower Bruche valley through numerical dating of the terrace deposits. The luminescence ages of the three fluvial terraces reveal distinct periods of aggradation in the URG. The uppermost sequences of the youngest (i.e. lowest) and middle terraces were deposited during the Younger Dryas (∼ 12–14 ka) and Marine Isotope Stage 3 (∼ 27–35 ka), respectively, while the oldest (i.e. highest) alluvial terrace has a minimum age of ∼ 200 ka.

Source: E&G Quaternary Science Journal

DOI: 10.5194/egqsj-74-169-2025

Authors: Madhurima Marik, Elena Serra, Gilles Rixhon, Frank Preusser

Institutions: University of Freiburg, Centre National de la Recherche Scientifique, Ecole Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES), Laboratoire Image, Ville, Environnement, Université de Strasbourg

Language: English

Topic: Geological formations and processes

Subfield: Earth-Surface Processes

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: diamond

Funder: German Academic Exchange Service New Delhi

Award: G4338366734