Holocene massive ground ice near the Sabettayakha River mouth, on the coast of the Gulf of Ob, Yamal Peninsula, northwest Siberia is studied. Three boreholes (Nr 12, 17 and 42) were drilled within the Holocene lagoon-marine floodplain of the Ob Bay and the first lagoon-marine terrace near the Sabettayakha River mouth in winter 2014 using a light portable drill. The drilling retrieved a 12 cm diameter core in an almost undisturbed condition. Massive ice was sampled from these boreholes for isotope, chemical and palynologic analyses. The ion concentration (%-equivalent - %-eq), salinity (S) and total dissolved solids (TDS) concentration was determined in newly melted snow, lake ice, sea ice and sea water. A single series of geochemical analysis of massive ice with other cryospheric objects was carried out for more reliable comparison and correct interpretation of geochemical data.

Cation and anion concentrations in the ice were measured immediately after the ice melted, in the Chemical-Analytical Centre of the Geographical Department of Lomonosov Moscow State University by ion chromatography "Stayer" with a conductivity detector. The limit for chloride ions is considered 0.02 μg/mL. The accuracy and precision over a wide concentration range, and total uncertainty (including random and systematic errors reported at the 95% confidence level) of anion and cation determinations were further estimated and the values were found to be sufficient for analysis of the ice.Data was submitted and proofread by Yurij K Vasil'chuk and Lyubov Bludushkina at the faculty of Geography, department of Geochemistry of Landscapes and Geography of Soils, Lomonosov Moscow State University.Funding was received from the Russian Science Foundation (Award nr. 19-17-00126, field research) and the Russian Foundation for Basic Research (Award nr. 18-05-60272, isotope analysis).