A more complete and detailed glacial history of the northwestern Chukchi margin—Implications for the existence and evolution of the East Siberian-Chukchi ice sheet

Abstract

It is speculated that an united East Siberian-Chukchi Ice Sheet (ESCIS) existed on the East Siberian-Chukchi margin during the Pleistocene era. However, details regarding the frequency of its occurrence and the intensity of each glaciation remain unclear. Critical information lies in the northern part of the East Siberian-Chukchi margin because this region preserves relatively complete glacial landforms and deposits, especially in areas of deep-water depths. In this paper, new full-coverage multibeam data from the outer shelf–ocean basin on the western side of the Chukchi Rise of the northwestern Chukchi margin are presented, and more complete submarine glacial landforms in this area are identified. In addition, we provide a more detailed interpretation of the entire glacial strata using a compilation of new sub-bottom profiler data. Interpreted glacial landforms and buried glaciogenic debris flows (GDFs) indicate that the western side of the Chukchi Rise was affected by the Chukchi Ice Sheet. Overall, the glacial landforms can be divided into two categories, i.e. those in an ice stream setting on the Southwestern Margin and an inter-ice stream setting on the Northwestern Margin. However, in the current inter-ice stream area, large old gullies and GDFs persist, indicating dynamic changes between the ice stream and inter-ice stream zones. Since the onset of glaciation began around ∼0.8 Ma, the study area has experienced a total of nine glaciations, including three intense glaciations, five intermediate glaciations, and 1 mild glaciation. Through a comparison with the GDFs on the eastern slope of the Arliss Plateau which locates further west of the Chukchi Rise, we infer the existence of at least four unified ESCISs during the Quaternary.