*2.1. Laboratory Sediment Analyses*

Analyses were performed using the topmost 31 samples, extracted from the eastern part of the profile and vertically covering a depth of 6 to 194 cm, thus excluding the natural soil of layer E (Figure 2a). Samples were extracted and stored in airtight bags to minimise errors when measuring water content. We densely sampled layers B and D to consequently capture the variability between the single obliquely bedded sand layers. Stratigraphic (sub)layers were described regarding colour and texture using the Munsell soil colour chart [39] and the German manual of soil mapping [40] respectively.

Further laboratory analyses of the sediments followed after the determination of the water content and sample preparation, including crushing of aggregates, separation of coarse components with a 2-mm sieve, and homogenising of the subsamples for carbon and portable energy-dispersive X-ray fluorescence spectrometer (p-ED-XRF) analyses in a vibrating disc mill.
