Infrared-Radiofluorescence (IR-RF) Dating of loess samples with independent age control from central Alaska – further investigations to establish IR-RF as a resilient dating method

• Applicant: Dr. Tobias Lauer
• Subject Area: Physical Geography
• Term: from 2018 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 418012553

Infrared Radiofluorescence (IR RF) dating is a method to determine the last sunlight exposure of sediment grains. The method is applied to potassium feldspar, has the potential to date back several 100 ka and the IR RF signal is characterized by high stability. Hence, the dating method is an important alternative to luminescence dating and it is especially relevant to establish chronological frameworks for Middle Pleistocene sediments. Until now, there are still several methodological issues related to IR RF, that need to be solved and only few dating laboratories apply IR RF. To obtain a higher acceptance of the method among dating specialists and Quaternary scientists further investigations are mandatory and it has to be outlined that IR-RF yields resilient chronological results. The aim of this research project is to test and further develop the IR RF method by applying IR RF to fine-grain samples with independent age control mainly taken from northern American loess-palaeosol sequences. The age of the samples ranges from the Holocene to the Middle Pleistocene. Dose recovery tests will be applied to modify the IR RF single aliquot protocol. Furthermore, experiments concerning the bleachability and the saturation behavior of the IR RF signal will be conducted. The reliability of final equivalent dose measurements and age determinations can be observed due to the given independent age control of investigated samples.Based on the results of the experiments, we intend to obtain a more detailed understanding of physics (electron pathways) behind the IR RF emission. Finally, the aim is to provide a dating approach that fulfills the high quality criteria needed in the field of Quaternary dating methods.

• DFG Programme: Research Fellowships
• International Connection: Canada
• Host: Professor Michel Lamothe