The Klettgau Formation (upper unit of the Keuper Group) underlies the Staffelegg Formation and belongs, at least partly, to the lower confining units. In JO and ZNO and partly in NL, it includes the local Keuper aquifer (Section 4.5.3.10). The Klettgau Formation was deposited in the southern part of the Central European Basin during the Late Triassic (Chapter 3). At this time, Northern Switzerland was dominated by variable, mostly terrestrial depositional environments (Fig. 4‑13).

Fig. 4‑13:Map of depositional environments during the Late Triassic (Carnian to Rhaetian) preserved in the Klettgau Formation

Refer to Fig. 4‑3 for a schematic representation of depositional environments. The north arrow refers to present-day geographic north. Mb.: Member.

Fig. 4‑14:Schematic synoptic section of the Klettgau Formation with its different members

On the right, comparison with correlative stratigraphic units in Germany (Etzold & Schweizer 2005, Geyer et al. 2023). Modified after Jordan et al. (2016b).