New data on the biostratigraphy (charophytes, nannofossils, mammals) and lithostratigraphy of the Late Eocene to Early Late Miocene deposits in the Swiss Molasse Basin and Jura Mountains

Abstract

In the northern Swiss Plateau and Jura Mountains, non marine Paleogene and Neogene deposits of the Swiss Molasse Basin or linked to the Upper Rhine Graben are examined in detail. The Late Eocene (Middle–Late Priabonian) is characterized by charophytes of the Vasiformis–Tuberculata Zone (Diegten Susswasserkalk) and Vectensis Zone (lower Tuberculata Superzone, Oberdorf Susswasserkalk, Terre jaune). The Rupelian and Early Chattian appear as little developed and extended. The Rupelian is characterized by charophytes of the Pinguis Zone (upper Tuberculata Superzone, basal Conglomerat de Porrentruy) and Major Zone (Conglomerat de Porrentruy, lower “Molasse alsacienne”, Marnes rouges). In the Neuchâtel region of central Jura, a paleokarst marine filling of UMM (Montmollin) yielded nannofossils of Early Rupelian (NP 21) age. Early Chattian sediments are for the first time precisely dated by small mammals (MP 25–26a) and typical charophytes of the Microcera Zone (Calcaire d’eau douce de Trois-Rods). The biostratigraphy of charophytes for the Early Miocene to early Late Miocene (MN 1–9) can also be defined more precisely ranging from Nitida Zone to Etrusca Zone. The biozonation of charophytes for the Swiss Paleogene and Neogene (SPN) is revised and completed by the creation of 11 assemblage zones SPN-EC 1–2 (Eocene charophytes, Late Eocene), SPN-OC 1–2 (Oligocene charophytes, Rupelian), SPN-OC 3–5 (Chattian), SPN-MC 1–2 (Miocene charophytes, Aquitanian), SPN-MC 3 (Burdigalian) and SPN-MC 4 (Langhian–Early Tortonian).