Drumlins in the Nordenskioldbreen forefield, Svalbard

摘要

The study of glacial landforms is important for understanding past subglacial processes and dynamics. The Nordenskioldbreen forefield hosts numerous streamlined landforms resulting from a late Holocene glacier advance. Here, we present a geomorphological map constructed from remotely sensed imagery of both the marine and terrestrial environments. Sixteen drumlin bedforms have been identified in the mapped forefield - ten terrestrial and six submarine. A sedimentological investigation of drumlins in the Nordenskioldbreen forefield shows that they are composed of pre-existing sediments draped by a thin layer of till which formed during the most recent advance of the glacier. Analysis of recent (2008-2012), high-resolution aerial imagery of all the glacier forelands in Svalbard suggests drumlin features are widespread. Here, we have identified 49 previously undocumented terrestrial glacier forefields, where subglacially streamlined landforms occur within the margins of the late Holocene glacier extent. Additionally, the location of 53 previously published submarine sites with streamlined landscape have been mapped. Thirty of these are sites with streamlines of late Holocene origin and 18 with Last Glacial Maximum (LGM) origin. Based on our detailed case study at the Nordenskioldbreen forefield, and remote sensing survey, we suggest that drumlins in Svalbard form predominantly in forefields of glaciers with low-elevation termini, in areas with abundant fine-grained sediments, and where the glaciers are able to advance into an area of unconstrained topography.