Lacustrine diatom oxygen isotopes as palaeo precipitation proxy - Holocene environmental and snowmelt variations recorded at Lake Bolshoye Shchuchye, Polar Urals, Russia

The diatom oxygen isotope composition (?18Odiatom) from lacustrine sediments helps tracing the hydrological and climate dynamics in individual lake catchments, is generally linked to changes temperature ?18Olake. Lake Bolshoye Shchuchye (67°53?N; 66°19? E; 186 m a.s.l) largest deepest freshwater reservoir Polar Urals, Arctic Russia. interpretation supported by modern (isotope) hydrology, local bioindicators such as chironomids, mass-balance modelling a digital elevation model of catchment. ?18Odiatom record follows decrease summer insolation northern hemisphere (NH) history. However, it displays exceptional, short-term variations exceeding 5‰, especially Mid Late Holocene. This centennial-scale variability occurs roughly contemporaneously with similar frequency Holocene NH glacier advances. larger advances catchment are unknown have not left any significant imprint on sediment record. As deep voluminous, about 30–50% its volume needs be exchanged isotopically different water within decades account for these shifts A plausible source light inflow snow, known transported surplus snow redistribution windward leeward side Urals. Here, we propose melt associated influx being dominant mechanism responsible observed first time drastic, been identified isotopes, which, Shchuchye, interpreted proxy palaeo precipitation and, millennial timescales, temperatures.