Fig. 3

Seismic lines across the Rhine Valley illustrating glacial overdeepening (modified from Pfiffner et al., 1997). A Seismic line Bonaduz shows a classic bow tie pattern originating from the U-shaped bedrock surface. The boundary between the Bonaduz Formation and the glacio-lacustrine sediments is calibrated by a well off the line. B Seismic line Chur Rossboden. The boundary between Rhine gravel and glacio-lacustrine sediments is calibrated by a well. The SE dipping reflections originated from the bedrock surface and overprint a bow tie structure caused by the U-shaped valley floor