Fig. 1

Geological map taken from Swisstopo (Gerber, 1927), showing the pattern of the surface geology and the location of the drillings and sections (stars on the figure), which provided key information for this work. These are the Brunnenbohrung Münsingen (Kellerhals and Häfeli, 1984), the Rehhag Drilling (Schwenk et al., 2022a, b) and the Neubrügg section (Lüthy et al. (1963), for which limited information about the chronological framework for the Quaternary sediments is available. We also used constraints offered by the Forstschotter gravel pit, the drilling RB 9201 (Kellerhals and Isler, 1983; Geotest, 1995) and that of the Hunzigebrügg (Zwahlen et al., 2021). Modified after Beck and Rutsch (1949), Spicher (1972) and Bandou et al. (2022). The map also shows the various sections we analysed through a gravimetric survey only (dashed blue lines) and through a combination of a gravity survey and modelling (blue lines). These are the following profiles: (1) Bümpliz, (2) Bremgarten, (3) Bern1, (4) Bern2, (5) Bern3, (6) Bern4, (7) Wabern1, (8) Wabern2, (9) Kehrsatz and (10) Airport. The Gürbe valley—Belpberg—Aare valley profile (11) was already published in a previous contribution (Bandou et al., 2022)