A New Model for Esker Formation Sheds Light on the Processes Within Subglacial Tunnels

©2019. American Geophysical Union. All Rights Reserved. Eskers are long sedimentary ridges that are widespread in current and previously glaciated landscapes. Eskers are believed to form when sediment carried by glacial meltwater gets deposited in subglacial tunnels, which given the importance of subglacial water for ice dynamics means that eskers can provide important information about the shape and dynamics of ice sheets and glaciers. To date, however, no physical model for their formation has been developed. Beaud et al. (2018, https://doi.org/10.1029/2018JF004779) present the first such model; they have linked an existing model for subglacial water flow with one for sediment transport, erosion, and deposition in mixed sediment/bedrock streams. The results of the model add new insights into the conditions which promote esker formation, the rate of supply of sediment to proglacial environments, and also suggest possible links between the water flow regime and the likely esker morphology