Moraine ridges in fjord-type, perialpine Lake Lucerne, central Switzerland

Abstract

Overdeepened valleys and troughs on the northern and southern margins of the central European Alps have been shaped during the Quaternary glaciations (Preusser et al. 2010). These valleys host a number of fjord-type lakes, remnants of formerly larger water bodies, which show various morphological features that reflect their glacial origin, similar to marine fjords. Among the most prominent of these features are large-scale transverse moraine ridges in Lake Lucerne, a perialpine lake situated in a branched valley system on the northern margin of the Alps (Fig. 1b, c). Fig. 1. Swath-bathymetric data and reflection-seismic profiles from Lake Lucerne, central Switzerland. ( a , d ) Shaded-relief images of the Nase Moraine and Chindli Moraine. Colour represents depth; greyscale for areas outside the lake. Acquisition system GeoAcoustics GeoSwath Plus. Frequency 125 kHz. Grid-cell size 1 m. Greyscale derived from swisstopo swissALTI3D elevation model. Labels: ch, chutes and channels; fa, fan-shaped deposit; cr, secondary crest. ( b ) Location of study area (red box; map from GEBCO_08). ( c ) Overview of Lake Lucerne; areas shown in (a) and (d) are marked by red rectangles. ( e , f ) Reflection-seismic profiles across the moraine ridges. VE×4. Acquisition system RCMG Centipede sparker, SIG single-channel streamer, IXSEA Delph acquisition unit. Vertical scale …