Holocene Glacial Dynamics of the Barentsøya ice cap, Svalbard

Abstract

This study investigates the glacial dynamics of Barentsjøkulen, a small ice cap located on Barentsøya, Svalbard. In order to reconstruct Barentsjøkulen’s glacial history, three geomorphological maps of the glacier forefields of its main outlet glaciers, Besselsbreen, Duckwitzbreen and Freemanbreen, were created. The maps cover a total area of ca. 117 km2 and were generated based on swath bathymetric datasets in combination with remotely sensed imagery. Ice front positions from ca. 1900 until present were reconstructed using historical data, oblique and vertical aerial imagery, satellite imagery and the GLIMS glacier database. The area of ice loss since the Little Ice Age was determined for Barentsjøkulen based on moraine positions under water and on land. Barentsøya’s landforms reveal a dynamic glacial history. The island was fully covered by the Svalbard-Barents Sea Ice Sheet during the Late Weichselian. After break-up of the ice sheet, a small ice cap remained on Barentsøya in the early Holocene - Barentsjøkulen. Barentsjøkulen has shown dynamic behaviour during the Holocene and has been in overall retreat since the Little Ice Age. An area of ice loss of ca. 147 km2 since the Little Ice Age was calculated. Duckwitzbreen and Freemanbreen have surged after the Little Ice Age - but not Besselsbreen. Crevasse-squeeze ridges, landforms often considered to be uniquely formed by surge-type glaciers, were detected in front of Besselsbreen. The use of crevasse-squeeze ridges as characterising landforms for surge-type glaciers should therefore be reconsidered. Landform assemblages in the mapped glacier forefields show little to no correspondence to existing landsystem models. More sophisticated landsystem models are required to capture the complexity of glacier types on Svalbard. This study improves the overall understanding of ice cap dynamics in eastern Svalbard during the Holocene.