¹⁴C ages of organic matter from Sentsa River floodplain outcrop and a small lithalsa were compiled from Arzhannikov et al., 2014.The middle Holocene age of the lake sediments was supported by ¹⁴C dates of char coal and peat sampled from the nearby outcrop at the contact with underlying sediments and in the peat cover (Arzhannikov et al., 2014). ¹⁴C measurements were conducted at the Radiocarbon Laboratory (lab code SOAN) of the Institute of Geology and mineralogy (Head L. Orlova), Russian Academy of Sciences, Siberian Branch.