These dataset contains multi proxy data from sediment core EN18218 obtained from Arctic glacial lake Rauchuagytgyn (67.7922°N, 168.7312°E) by piston coring during the Chukotka 2018 expedition (Siberia). We provide original count data of diatom species from 53 samples along a ca. 5.5 m interval in the sediment core, next to nitrogen and mercury concentrations. The data are complementary to the sedimentological and radiocarbon data published in an earlier data set by Vyse et al. 2021. The data sets provides, calculated from the original data, estimated accumulation rates based on a revised age model explained in the manuscript for diatom valves (diatom accumulation rate, DAR), organic carbon (organic carbon accumulation rates, OCAR), and mercury (Hg accumulation rates, HgAR).

Zeiss Axioscope 5 Light microscope with an Axiocam 208 color camera attached, equipped with a Plan-Apochromat 100x/1.4 Oil Ph3 objective at 1000x magnification. The data provided here describe original count data of diatom valves attributed to diatom species.