ARCTIC HYDROCLIMATE AND VEGETATION VARIABILITY FROM 0-200 KA: STABLE ISOTOPE AND BIOGEOCHEMICAL RECORDS FROM LAKE EL'GYGYTGYN, NE RUSSIA

A drill core recovered from Lake El’gygytgyn (Lake E) in northeastern Russia provides the only continuous, high-resolution, terrestrial record from the Arctic spanning the last 3.6 Ma. As anthropogenic climate change drives ever higher Arctic temperatures, paleoclimate and paleoenvironmental records of past warm periods become increasingly pertinent. Here, we examine organic matter in Lake E sediments to reconstruct temperature, hydroclimate, and landscape vegetation variability. Our record spans the interval of 0-200 ka, encompassing both marine isotope stage (MIS) 5 and MIS 7, two periods thought to be as warm as, or warmer than present, providing insight about climate and vegetation change associated with continued Arctic warming. We apply organic geochemical techniques including compound-specific hydrogen isotope analysis of plant leaf waxes (n-alkanes) and the MBT/CBT proxy based on branched glycerol dialkyl glycerol tetraethers to assess hydroclimate and temperature variability, respectively. We examine vegetation turnover via the distribution of long-chain n-alkanes coupled with variations in pollen assemblages. Trends observed in our new records indicate significant shifts in vegetation, temperature, and hydroclimate associated with local, regional, and global climatic changes on glacial-interglacial timescales.