The Eltville Tephra (Western Europe) age revised: Integrating stratigraphic and dating information from different Last Glacial loess localities

Abstract

The Eltville Tephra (ET) is an important stratigraphic marker bed in the Western European loess stratigraphy at the boundary between the regional Last Glacial Maximum (LGM) in the sense of the maximum extent of glaciation of the Scandinavian ice sheet and a ‘terrestrial’ LGM with the highest degree of aridity and coldness. Stratigraphic marker beds such as tephra layers are commonly dated at more than one location, and often with more than one method. The sediments surrounding the ET were dated 87 times at 15 localities with different luminescence techniques yielding ages between 13.5 and 49.6ka. Based on individual sections, the deposition of the ET was supposed to have taken place between 20 and 23ka. This raises the question of whether a quantitative combination of individual ages can give a reproducible common age, including uncertainties. After screening the dataset and applying selection criteria, a Bayesian resampling approach is applied to obtain a common age consistent with a high percentage of observations from multiple localities.Four new luminescence ages bracketing the ET and two ages directly generated from the tephra horizon are presented and combined with all available data. The 1σ age range of the Bayesian age modelling yields a deposition age between 23.2 and 25.6ka, which is in excellent agreement with two new luminescence ages from the tephra of 24.1±1.9ka (quartz) and 24.3±1.8ka (pIRIR290) and a peak of volcanic minerals in the Dehner Maar core around 24.3ka. This age is clearly older than previously suggested for the ET volcanic eruption, but fits better with stratigraphic and paleoenvironmental evidence. Therefore, the ET was deposited during phases of strong aeolian activity of the Greenland Stadial 3. Additionally, for the first time, a correlation can be made between the ET and tephra layers recognized in the Eifel Maar lake cores.