Holocene subaqueous landslide dynamics in the Lake Siljan‐Orsasjön Basin, south‐central Sweden

The Siljan‐Orsasjön Basin in south‐central Sweden hosts two prominent lakes. A 100 m deep channel extends approximately 52 km across the basin but does not form a continuous connection between the lakes today. Geophysical mapping, including multibeam bathymetry and sub‐bottom profiling, revealed several landslide areas associated with the steep slopes of this channel and redistributed mass‐wasted glaciolacustrine varved sediments as well as later‐deposited laminated lake sediments. To assess the timing and processes of sediment displacement within these subaqueous landslide areas, sediment cores were retrieved and radiocarbon dated. The results uncovered a complex stratigraphy and ruled out the possibility of a single landslide event. Instead, several events have occurred over the past 10,000 years, beginning shortly after the deglaciation.