This dataset includes all biomarker (alkenone saturation – UK37, and alkane distribution) and geochemical (XRF – log(Br/Ti)) data presented in van der Bilt et al. 2025 – published in Nature Communications. The data derive from a lake sediment record from Svalbard – core HAP0212 (79 °N, 11 °E) – and were generated using gas chromatography (GC: alkenone and alkane data) and X-Ray Fluorescence (XRF) core scanning (log(Br/Ti)) at the geochemistry facility of the Lamont Doherty Earth Observatory (LDEO) and the EARTHLAB sediment facility at the University of Bergen (UiB), respectively. All of the provided data are shown in Figs. 2, 3, 4, and 5 of the paper. Additional details are found in the readme file.