Dating moraine deposits using luminescence from rock surfaces
Final Report Abstract
Dating moraine deposits is not a trivial matter. The currently most used dating methods in this environment (CN-dating and radiocarbon dating) cannot always provide reliable ages because one or more of their requirements cannot be met. The project set out to prove that: (1) RSLD can be used as an alternative method for these deposits, which can be used as a supplementary method, which is always good to have, but more importantly as the method of choice for the many deposits where neither radiocarbon dating nor CN-dating can be applied. (2) Rock surface luminescence depth profiles can be used to identify boulders which are not suited for CN-dating. Two successful field campaigns where carried out sampling (I) the Vimmerby moraine in southeastern Sweden as a deposit from a foreland glacier, (II) a diamicton at the type locality of the Rissian glaciation in Biberach an der Riss and three different moraine deposits in the proximity of a modernday alpine glacier in the Ochsental (Austria). The first results dating a moraine deposit from the Austrian alps showed very promising results that the methodology can be used to date these kinds of deposits. The data from the Vimmerby site is strongly supporting these results. These data have so far only been published as conference contributions. Both data sets show that >50% percent of all sampled boulders show signs of predepositional exposure and >30% of the samples can be used for dating. This provides good chances that the method can be broadly applied to moraine deposits and is a great success, but also lead to difficulties in the project execution as the sample time used for sample preparation was underestimated in the project planing. In the course of the project measures were undertaken to accelerate the process of sample preparation, so that at least the samples from the Vimmerby moraine could now completely be processed and dated. The second goal of this project was reached by the complementary study of two boulders used also used for CN-dating. This was done by a very novel approach using an IRPL imaging system. The dating of the same moraine using RSLD could not be carried out in time and a further sampling of boulders successfully dated by CN unfortunately prevented by bad weather conditions during the fieldwork planned by our Austrian collaborators. The results will be published as soon as possible.
Publications
- 2017. First rock surface luminescence profiles in moraine boulders from Malta Valley, Austria. International Luminescence and Electron Spin Resonance Dating Meeting, Capetown, Southafrika
Rades, E.F., Sohbati, R., Lüthgens, C., Jain, M., Murray, A.S.
- 2018. Finding the most suitable moraine boulders for dating using luminescence-depth profiles, UK Luminescence and ESR Meeting 2018, Sheffield, England
Rades, E.F., Sohbati, R., Alexanderson, H., Jain, M., Murray, A.S.
- 2018. First luminescence-depth profiles from boulders from moraine deposits: Insights into glaciation chronology and transport dynamics in Malta valley, Austria. Radiation Measurements 120, 281–289
Rades, E.F., Sohbati, R., Lüthgens, C., Jain, M., Murray, A.S.
(See online at https://doi.org/10.1016/j.radmeas.2018.08.011) - 2019. Ages and transport history of moraine boulders from rock surface luminescence profiles. INQUA2019, Dublin, Ireland 2017 Capetown
Rades, E.F., Sohbati, R., Lüthgens, C., Alexanderson, H., Jain, M., Murray, A.S.
- 2019. Luminescence rock surface profiles from moraine boulders: useful for dating and transport histories. Geophysical Research Abstracts 21
Rades, E.F., Sohbati, R., Alexanderson, H., Jain, M., Murray, A.S.
