Glacial Vermicular Ridge Features on Axel Heiberg Island, Nunavut, Canada

Abstract. Vermicular Ridge Features (VRFs) comprise a series of ridges and troughs with a circular, sinuous, and anastomosing morphology composed of clast-rich sandy diamict. VRFs were first reported on the south coast of Devon Island, Nunavut, Canada, in the Dundas Harbour region. Here, we document the presence of VRFs near Mokka Fjord on Axel Heiberg Island, Nunavut, Canada. We utilize field observations, ultra high resolution LiDAR, and ground penetrating radar to characterize and compare the morphometry and sedimentology of VRFs near Mokka Fjord to other periglacial, paraglacial, and glacial landforms. VRFs near Mokka Fjord have a diameter ranging from 6 to 37 m and reach up to 1.5 m in height. They comprise clast-rich glaciofluvial sediment and till. A leading periglacial (i.e., segregation ice features/lithalsas) and glacial (i.e., ring-ridge moraines and kame/kettled terraces) origin are presented. We interpret Mokka Fjord VRFs to be an ice-marginal feature resulting from paraglacial ablation of buried glacial ice producing a hummocky ring-ridge moraine comprised of ice marginal and supra- and englacial debris. This formation mechanism would infer a largely polythermal glacial environment with limited water supply. Likely from occasional warm-based periods at the ice margins which may allow sediment output and ice burial from basal ice debris redistribution or the thinning and subsequent burial of snout ice from glaciofluvial outwash.