Late Quaternary depositional and glacial history of the Arliss Plateau off the East Siberian margin in the western Arctic Ocean

Sedimentary stratigraphy and facies analysis along with seismostratigraphic and multibeam bathymetrydata are used to reconstruct the last glacial impact on the Arliss Plateau (AP) and attendant sedimen-tation in the adjacent Chukchi Basin (CB) in the western Arctic Ocean off the East Siberian margin.Sediment core ARA02B/16B-GC from the AP lower slope captures glacier-related depositional historyduring the last estimated ca. 100 ka (Marine Isotope Stage, MIS 1 to 5c) based on regional lithostrati-graphic correlation. The sedimentary record shows distinguishable interglacial (interstadial) and glacial(stadial) patterns. The identified sedimentary facies reflect several modes of glaciogenic deposition bydrifting icebergs, suspension settling from turbid meltwater plumes and/or detached underflows, andturbidity currents. Based on strong seismic reflectors related to lithological boundaries, a downslopesubbottom profile from AP to CB is divided into seismostratigraphic units (SSU) 1 and 2 corresponding inthe core record to MIS 1e3 and MIS 3-5c, respectively. An acoustically transparent lens within SSU 2correlates on the upper slope to debris lobes downslope from the AP top covered by megascale glaciallineations. This geomorphic/sedimentary pattern indicates a glacial erosional impact on the AP andproglacial deposition of eroded sediments on the slope and in the basin. Based on the developed sedi-ment stratigraphy and facies analysis, the last debris lobe horizon was deposited in glacial/deglacialenvironments during late MIS 4 to early MIS 3. The absence of similar glaciogenic debris lobes within SSU1 indicates no direct glacial impact on the AP during the Last Glacial Maximum (LGM). These resultssuggest that the last glacial erosion of the AP occurred during or immediately after MIS 4, possibly relatedto major glaciation in northern Siberia at ~50e70 ka