Morphologic and seismic stratigraphic analysis of Quaternary deposition on the western Arctic continental margin: Insights into the extent and behavior of the East Siberian Ice Sheet

Abstract

Extensive mapping of the glaciogenic sedimentary and geomorphic features can enhance our understanding of the spatial extent and behavioral nature of the former ice sheets. The subsurface geological conditions of the high-latitude continental margin continue to be affected by the past ice sheets, such as glacial isostatic uplift and eustatic sea level rise, even after the ice sheet disappeared. Therefore, reconstructing ice-sheet history is crucial for identifying areas that may be at risk of slope failure or for understanding the migration and expulsion of fluids in the subsurface strata. Previous studies in the Chukchi-East Siberian margin in the western Arctic Ocean revealed multiple ice sheet expansions during the Quaternary glacial periods. In this study, we extended the previous seismostratigraphic interpretation of the western Chukchi Rise toward the East Siberian margin to compare characteristics of ice masses in two adjacent regions that were likely grounded by the same ice sheet, known as the East Siberian Ice Sheet (ESIS). The acoustically transparent deposits well defined in the seismic data and can be interpreted as glaciogenic debris flows, till sheets, and recessional moraines. The migration of glacial sediment depocenters from the Chukchi Basin through Kucherov Terrace to the upper slope and outer shelf of the East Siberian margin suggests a decrease in sediment transportation into the deeper area by southern-sourced grounded ice over time. This observational result may indicate a change in the glacial regime from a wet-based dynamic to a dry-based polar conditions, a reduction in vertical and lateral extent of the ice sheet, and/or a decrease in the amount of erodible subglacial sedimentary strata. The development of grounded-ice on the East Siberian margin is similar to the glaciations on the western Chukchi Rise, suggesting that ESIS grew significantly with merging and interaction of the expanded ice masses from both regions.