Late Holocene history of Sefströmbreen in Ekmanfjorden, Svalbard

Abstract

There is limited documentation of complete surge cycles from Svalbard. Since the Little Ice Age, multiple surge-type glaciers in Svalbard have been undergoing continuous retreat. This has led to the formation of combined terrestrial and marine terminating margins, as well as newly exposed terrain, featuring glacial landforms such as crevasse-squeeze ridges, which are diagnostic landforms of surge-type behavior, and reflect the subglacial regime. This Master’s thesis investigates the ice flow pattern of Sefströmbreen, a surge-type glacier in Ekmanfjorden, Svalbard, by integrating modern and historical observations of the terrestrial and marine environment. This was achieved by combining high-resolution bathymetry of the seafloor in Brevika with field observations and remote sensing techniques. The main objective is to investigate how the ice flow pattern from the various stages of the surge cycle is reflected in the marine and terrestrial environment. The first record of Sefströmbreen surging occurred in 1896, and a second surge commenced in 2024. In between, the glacier retreated approximately 14 km into Brevika Bay, characterized by a three-structured margin where the central parts were marine terminating and the outer sections were terrestrial terminating.