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).

We determined the THg in solid material by thermal decomposition, amalgamation and atomic absorption spectrophotometry using a Direct Mercury Analyzer (DMA-80 evo; MLS-MWS GmbH).