Glacigenic bedforms such as multiple glacial lineations and moraines on the Chukchi and East Siberian margins reveal recurrent waxing and waning by voluminous ice masses. Despite their paleoclimatic significance, the timing, geographic distribution, and mechanisms of these glaciations remain inadequately understood. To enhance our understanding of the Quaternary Arctic glacial history, we study high-resolution swath bathymetry and subbottom profiling data with lithostratigraphy and provenance of four sediment cores. These data characterize deposits of the last two glaciations at the Chukchi margin and adjacent basins. In all cores, multiple peaks of plagioclase are prominent in both glacial intervals, probably reflecting predominant glacigenic input from the East Siberian Ice Sheet (ESIS). Peaks of dolomite and quartz for tracing the Laurentide Ice Sheet sources occur around the last glacial/deglacial interval and in sediment preceding the penultimate glaciation. By integrating seismostratigraphy with sediment cores, we constrain the formation of mid-slope moraines on the western side of the Chukchi Rise to the penultimate glaciation (estimated age range MIS 4 to 6). Considering the coeval glacial erosion off the East Siberian margin, our results confirm that the ESIS at that time extended to water depths of ~650/950 m on the Chukchi Rise/East Siberian margin. In comparison, the last ESIS (MIS 2 to possibly 4) was smaller, with the identified seafloor imprint limited to water depths of ~450 m on the Chukchi Borderland, while its extent on the East Siberian margin remains to be determined.

High-resolution seafloor mapping provides insights into the dynamics of past ice-sheets/ice-shelves on high-latitude continental margins. Geological/geophysical studies in the Arctic Ocean suggest widespread Pleistocene ice grounding on the Chukchi–East Siberian continental margin. However, flow directions, timing, and behavior of these ice masses are not yet clear due to insufficient data. We present a combined seismostratigraphic and morphobathymetric analysis of the Chukchi Rise off the northwestern Chukchi margin using the densely acquired sub-bottom profiler (SBP) and multibeam echosounder (MBES) data. Comparison with deeper airgun seismic records shows that the SBP data cover most of the glaciogenic stratigraphy possibly spanning ca. 0.5–1 Ma. Based on the stratigraphic distribution and geometry of acoustically transparent glaciogenic diamictons, the lateral and vertical extent of southern-sourced grounded ice became smaller over time. The older deposits are abundant as debris lobes on the slope contributing to a large trough mouth fan, whereas younger till wedges are found at shallower depths. MBES data show two sets of mega-scale lineations indicating at least two fast ice-streaming events of different ages. Contour-parallel recessional morainic ridges mark a stepwise retreat of the grounded ice margin, likely controlled by rising sea levels during deglaciation(s). The different inferred directions of ice advances and retreats reflect complex geomorphic settings on the borderland. The overall picture shows that the Chukchi Rise was an area of intense interaction(s) of different ice-sheets/ice-shelves. In addition to glaciogenic deposits, we identify a number of related or preceding seabed features including mounds, gullies/channels, and sediment waves.