The geochronology was established on the basis of Accelerator Mass Spectrometry (AMS) radiocarbon dates using a Mini Carbon Dating System (MICADAS) implemented at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI). Further preparation for AMS radiocarbon dating bulk samples were carried out by the Laboratory of Radiocarbon dating and electron microscopy of the Institute of Geography of the Russian Academy of Sciences. Their radiocarbon ages were measured by accelerated mass spectrometry (AMS) at the Center for Applied Isotope Studies of the University of Georgia (USA) using the 1.5SDH Pelletron AMS. Sediments were freeze-dried manually homogenized, and split into sub-samples for further analyses: grain-size distribution, mass-specific magnetic susceptibility, total elemental carbon (TC) and nitrogen contents (TN), total organic carbon content (TOC), the δ¹³C of TOC. The total inorganic carbon (TIC) content was calculated by subtracting TOC from TC. For TOC and δ¹³C analyses, samples were decalcified for 3 h at 95°C by adding 1.3 N HCl.