Lake floor morphology and sediment architecture of lake torneträsk, northern sweden

Abstract

Here we present datasets from a hydroacoustic survey in uly 2011 at Lake orneträsk, northern weden. Our hydroacoustic data exhibit lake floor morphologies formed by glacial erosion and accumulation processes, insights into lacustrine sediment accumulation since the beginning of deglaciation, and information on seismic activity along the Pärvie Fault. Features of glacial scouring with a high‐energy relief, steep slopes, and relative reliefs of more than 50 m are observed in the large ‐basin. The remainder of the lacustrine subsurface appears to host a broad variety of well preserved formations from glacial accumulation related to the last retreat of the Fennoscandian ice sheet. Deposition of glaciolacustrine and lacustrine sediments is focused in areas situated in proximity to major inlets. Sediment accumulation in distal areas of the lake seldom exceeds 2 m or is not observable. We assume that lack of sediment deposition in the lake is a result of different factors, including low rates of erosion in the catchment, a previously high lake level leading to deposition of sediments in higher elevated paleodeltas, tributaries carrying low suspension loads as a result of sedimentation in upstream lakes, and an overall low productivity in the lake. A clear off‐shore trace of the Pärvie Fault could not be detected from our hydroacoustic data. However, an absence of sediment disturbance in close proximity to the presumed fault trace implies minimal seismic activity since deposition of the glaciolacustrine and lacustrine sediments.

Key words:

• Lake Torneträsk
• Scandes Mountains
• northernmost Sweden
• lake floor morphology
• lacustrine sedimentation
• Weichselian glaciation

Acknowledgements

We would like to thank the staff of the Abisko Scientific Research Station and in particular Thomas Westin and Christer Jonasson for logistical and technical support during the field research and two anonymous referees who helped improving the manuscript. Funding was provided by the Institute of Geology and Mineralogy at the University of Cologne, Germany, and the Climate Impact Research Centre at the Umeå University, Sweden.