The Eastern Chukotka is considered a unique permafrost region where massive ice bodies are widespread. However, the origin and age of these ice formations are often discussed. The age of the massive ice of Chukotka was established for the first time using AMS 14C dating. It was revealed that three massive ice bodies on the coast of Mechigmen Bay were formed at the end of the Late Pleistocene: a) near the Akkani site, 21,612 to 22,147 cal BP; b) near the Lavrentiya settlement, 27,553 cal BP; and c) near the Lavrentiya settlement, 22,193 cal BP. Stable isotope values in the studied massive ice vary in a rather wide range by about 10‰ for δ18O values (from –14.8‰ to –24.5‰) and about 75‰ for the δ2H values (from –116‰ to –191‰). The studied massive ice bodies are of intrasedimental genesis and formed epigenetically during the final stage of MIS2 (22–27 cal ka BP).

Freshwater ecosystems are responsible for a large proportion of global methane emissions to the atmosphere. The radiocarbon (14C) content of this aquatic methane is useful for determining the age and source of this important greenhouse gas. Several methods already exist for the collection of aquatic methane for radiocarbon analysis, but they tend to only sample over short periods of time, which can make them unsuitable for characterizing aquatic methane over longer timespans, and vulnerable to missing short-term events. Here, we describe a new time-integrated method for the collection of aquatic methane that provides samples suitable for radiocarbon analysis, that are representative for periods of up to at least 16 days. We report the results of a suite of tests undertaken to verify the reliability of the method, and the 14C age of aquatic methane from field trials undertaken at sites within Scotland, UK. We believe that this new method provides researchers with a simple approach that is easily deployable and can be used to collect representative time-integrated samples of methane for radiocarbon analysis from a wide range of aquatic environments.