Eocene-Pliocene time scale and stratigraphy of the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB)

Abstract

We present a general stratigraphic synthesis for the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB) from Eocene to Pliocene times. The stratigraphic data were compiled both from literature and from research carried out by the authors during the past 6 years ; an index of the stratigraphically most important localitites is provided. We distinguish 14 geographical areas from the Helvetic domain in the South to the Hanau Basin in the North. For each geographical area, we give a synthesis of the biostratigraphy, lithofacies, and chronostratigraphic ranges. The relationships between this stratigraphic record and the global sea-level changes are generally disturbed by the geodynamic (e.g., subsidence) evolution of the basins. However, global sea-level changes probably affected the dynamic of transgression-regression in the URG (e.g., Middle Pechelbronn Beds and Serie Grise corresponding with sea-level rise between Ru1/Ru2 and Ru2/Ru3 sequences, respectively) as well as in the Molasse basin (regression of the UMM corresponding with the sea-level drop at the Ch1 sequence). The URGENT-project (Upper Rhine Graben evolution and neotectonics) provided an unique opportunity to carry out and present this synthesis. Discussions with scientists addressing sedimentology, tectonics, geophysics and geochemistry permitted the comparison of the sedimentary history and stratigraphy of the basin with processes controlling its geodynamic evolution. Data presented here back up the palaeogeographic reconstructions presented in a companion paper by the same authors (see Berger et al. in Int J Earth Sci 2005).

Earliest record of rhinocerotoids (Mammalia: Perissodactyla) from Switzerland: systematics and biostratigraphy

“…They belong to the Conglomérats de Porrentruy, Meeressand and Septarienton stratigraphical groups (Berger et al 2005a, b;Picot et al 2008). Whereas three transgression-regression cycles are known within the Rhine Graben during the Oligocene, only the first two are recorded in the Porrentruy region (Ajoie district), and only the second one in the Laufen basin (Fig.…”

The position of the Rupelian/Chattian boundary in the southern Upper Rhine Graben based on new records of microfossils

“…the Dannemarie Basin in the west and the Sierentz-Wolschwiller Graben in the east (Roussé 2006). Towards the Rhinegraben centre, the grain sizes diminish considerably (Hinsken et al 2007) and the basin fill consists mainly of lacustrine to marine sands, silts and marls (Berger et al 2005b). …”

“…Berger et al 2005b;Grimm et al 2011b). This succession includes the fossiliferous Foraminiferenmergel (Foraminifera Marls) and the dysoxic to anoxic, finely laminated Fischschiefer (Fish Shales), the latter indicating the maximum flooding and marine conditions throughout the basin (Roussé 2006;.…”

Iberomeryx minor (Mammalia, Artiodactyla) from the Early Oligocene of Soulce (Canton Jura, NW Switzerland): systematics and palaeodiet

“…The biochronological framework is based on the European Land Mammal Ages (ELMA) Fig. 2 Palaeogeographical map of the southern Rhine Graben and the north-central Jura Molasse during the Late Rupelian, highlighting the regression of the second incursion of the Rhenish sea (modified after Berger et al 2005b;Pirkenseer 2007;Picot et al 2008) defined by the succession of European mammal reference levels (MP; Schmidt-Kittler 1987) and the Paleogene geological time scale (Luterbacher et al 2004). …”