Sediment cores were recovered using a hand-held Cobra Pro (Atlas Copco) core drilling system with a 60 mm diameter open corer. One-meter segments were retrieved and assessed in the field for sedimentological features, including estimations of grain size, carbonate content, humus content, and redox features (AG Boden 2005, 2024). Colour descriptions were carried out using the Munsell Soil Color Chart. The exact positions of the drilling points were recorded using a differential GPS device (TOPCON HiPer II). The cores were photographed, documented and sampled at 5–10 cm intervals for subsequent laboratory analyses.
Bulk samples from five selected cores (RK1, RK3, RK13, RK15, RK17) were freeze-dried, sieved (2 mm), and weighed. Total carbon (TC), total nitrogen (TN), and total sulfur (TS) contents were measured using a CNS analyzer (Vario EL cube, Elementar). Inorganic carbon (TIC) was determined using calcimeter measurements (Scheibler method, Eijkelkamp). Organic carbon (TOC) was calculated as TOC = TC − TIC.
For the grain size analyses, sediment samples were first sieved to <2 mm and subsamples of 10 g were treated with 50 ml of 35% hydrogen peroxide (H₂O₂) and gently heated to remove organic matter. Following this, 10 ml of 0.4 N sodium pyrophosphate solution (Na₄P₂O₇) was added to disperse the particles, and the suspension was subjected to ultrasonic treatment for 45 minutes. The sand fraction was analysed by dry sieving and classified into four size classes: coarse sand (2000–630 µm), medium sand (630–200 µm), fine sand (200–125 µm), and very fine sand (125–63 µm). Finer fractions were determined using X-ray granulometry (XRG) with a SediGraph III 5120 (Micromeritics). These included coarse silt (63–20 µm), medium silt (20–6.3 µm), fine silt (6.3–2.0 µm), coarse clay (2.0–0.6 µm), medium clay (0.6–0.2 µm), and fine clay (<0.2 µm).
Sediment were sampled on expedition HE625 of the R/V Heincke in July 2023 at 50 stations spread evenly over the muddy sediment region in southeast of the island of Helgoland (southeastern North Sea). At each station, two replicate samples were taken with a van Veen grab with a sampling area of 0.1 m² and a penetration depth of 10 cm. A subsample of the upper 6 cm of sediment was taken using a coring tube from the second grab with a diameter of 4.5 cm. The grain-size distribution was determined based on laser-diffraction granulometry using a CILAS 1180L particle size analyzer. Another sub-sample of 40 g of sediment were dried, weighed, and incinerated at 500 °C for five hours to estimate the organic content (%) as weight loss on combustion. Sediment variables included organic carbon content (OC), sediment composition (percentages of sand, silt, and clay), grain size (d10, d50, d90), and statistical measures of sediment grain size distribution (skewness, sorting, kurtosis).
Oxbow lakes are continuous archives of flood events. On 28th June 2022 a 7.5 m long bottom sediment core (S1: 53.24758°N and 14.46271°E, 2.4 m b.s.l.) was collected from an oxbow lake in the Lower Odra Valley, NW Poland. Drilling was conducted using an Instorf sampler (Russian type; chamber dimension: 10 x 50 cm), onboard a "Manat" catamaran motorboat. After core recovery, each half-metre section was packed into a PVC tube and kept in cool rooms with a constant temperature. Samples were collected every 4 cm. For the first 2 m of the core grain-size, geochemical and Chironomidae analyses as well as radiocarbon dating were performed, which allow to identify flood events in the last 3200 years.
Continuous sediment profiles were taken from ravine slopes at the Nesseltalgraben site in the Northern Calcareous Alps (SE Germany, 47.6567°N 13.0467°E, 560-582 m a.s.l.) in October 2016. The profile consists of fine-grained lacustrine-palustrine sediments overlain by several metres of glacifluvial gravels and lodgement tills of the Last Glacial Maximum and underlain by a diamicton. High-resolution (2 mm steps) element counts (Ca, S, Si, K, Ti, Mn, Fe, Zn, Rb, Sr, Zr) were obtained with an XRF core scanner (Itrax, Cox Analytical Systems, Sweden). Organic geochemistry (total organic and inorganic carbon, total nitrogen, total sulphur) was analysed with an elemental analyser (Euro EA, Eurovector, Germany), grain size with a laser diffractometer (Beckman-Coulter LS 200). The sediment profiles were compiled to a composite record of 21 m length. The age model bases on 29 radiocarbon analyses of macroscopic terrestrial plant remains (byrophytes, plant debris, monocots, wood, and twigs) and a previously discovered paleomagnetic anomaly assigned to the Laschamp event. The age model covers the period 59 to 29.6 ka cal BP and assigns the record to Marine Isotope Stage (MIS) 3. The sediment record shows rapid changes in lithology, sedimentology, and geochemistry related to Dansgaard-Oeschger climatic events.