Glacial geomorphology of Trygghamna, western Svalbard - Integrating terrestrial and submarine archives for a better understanding of past glacial dynamics

Abstract

Detailed geomorphological mapping was carried out in the terrestrial and submarine forefields of Protektor-, Harriet- and Kjerulfbreen in Trygghamna, western Svalbard, based on high-resolution aerial images and bathymetric data. The mapping reveals that crevasse-squeeze ridges (CSRs) are only observed on land in the forefield of the surge-type Harriet- and Kjerulfbreen, and recessional moraines are only formed at the sea floor in relation to the retreat of these two glaciers. Different factors affect the preservation potential and formation of landforms between the two environments that could explain the absence of CSRs in the submarine environment and the terrestrial forefield of Protektorbreen. The landform assemblage in Trygghamna does not comply well with existing surge-type glacier landsystem models. We present a conceptual landsystem model for surge-type glaciers with combined terrestrial and marine margins, based on the geomorphological archive from Trygghamna. The contrast between the landform assemblages demonstrates how differences in the thermal regime result in different glacier behavior between the warm-based submarine margins and the inactive cold-based terrestrial margin. This study emphasizes the importance of integrating data from both archives to reconstruct past glacier behavior and understand the effect of different glacial dynamics and environments on the preservation potential of sediments and landforms.