Dynamics of Paraglacial Beach Development in Front of Rapidly Retreating Marine-Terminating Glacier – Hansbreen, Svalbard

Abstract

This study investigates the formation and controlling mechanisms of shorelines in the forefield marine-terminating glacier in Svalbard (Hansbreen, SW Spitsbergen), utilising multi-temporal remote sensing, sedimentological analysis and ground-penetrating radar (GPR). Since the end of the Little Ice Age (LIA), glacier retreat has exposed nearly 10 km of new coastline, with a marked acceleration with intensified deglaciation. Digital Shoreline Analysis System (DSAS) results reveal widespread coastal erosion characterised by high spatial variability. This variability is more strongly associated with contrasting wave-exposure conditions within the fjord than with distance to the present glacier front, which explains little of the observed shoreline change. Sea ice acts as a seasonal regulator—limiting the duration of wave activity rather than directly exerting thermodynamic or mechanical magnitude. Furthermore, sedimentological and geophysical data show a clear transition from heterogeneous glacigenic environments near the terminus to progressively reworked, wave-dominated systems. Grain-size distributions and internal stratigraphic architectures revealed by GPR surveys reflect greater sorting efficiency and morphological organisation as distance from active sediment sources increases. Ultimately, Hansbreen forefield represents a strongly process-structured paraglacial system, where coastal evolution is governed by the spatial distribution of wave energy and exposure history rather than direct glacial forcing or fluctuations in sediment supply.