Claudius Pirkenseer

Reworked microfossils as a paleogeographic tool

The abundant occurrence of reworked microfossils within the paleogeographically restricted Upper Rhine Graben of central Europe represents a unique opportunity to investigate their inherent information, allowing new insights into the paleogeographic framework and past sedimentary pathways. In the late Rupelian and early Chattian a transgression-regression cycle linked to the global Ru2–Ru3 sequences affected the entire Upper Rhine Graben basin, leading to the deposition of a thick marine to lacustrine series. The occurrences of abundant reworked planktonic foraminifera are grouped into several events that are linked to intervals of increased clastic input during regressive phases. The biostratigraphic ranges of the reworked taxa indicate Late Cretaceous, Ypresian, Lutetian, and Bartonian–Priabonian ages for the sediment sources. The reworking originated from related west alpine source deposits via a northward-draining fluviatile system. A fast uplift of Priabonian and older deposits within the alpine realm during the late Rupelian is accordingly inferred, confirming the increased rate of the mesoalpine orogeny at that time. The careful analysis of reworked microfossil assemblages thus provides a valid tool for future paleogeographic, tectonic, and provenance studies.

New skeleton from the early Oligocene of Germany indicates a stem-group position of diomedeoidid birds

We report a new specimen of the extinct procellariiform species Diomedeoides brodkorbi (Aves, Diomedeoididae) from the early Oligocene (Rupelian) of Rheinweiler in southwestern Germany. The well-preserved partial skeleton allows the recognition and reassessment of new osteological details that bear on the phylogenetic affinities of diomedeoidids. The presence on the coracoid of a deeply excavated, cup-like facies articularis for the scapula suggests a stem group position of the Diomedeoididae within Procellariiformes, because this trait also occurs in stem-group representatives of several avian groups, as well as in Mesozoic non-neornithine birds, and is a plesiomorphic character. We hypothesize that the similarities of Diomedeoides to extant southern storm-petrels (Oceanitinae), such as the long mandibular symphysis, the small processus supracondylaris dorsalis and the long legs are plesiomorphic for Procellariiformes.

Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea

Cold-water coral (CWC) ecosystems occur worldwide and play a major role in the oceans carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago). However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata) that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents

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

This study analyses the regressive phase of the marine Froidefontaine Subgroup and the subsequent fluvio-lacustrine Niederroedern formation in the southern Upper Rhine Graben during the Late Rupelian and the position of the Rupelian/Chattian boundary. The study is based on the sedimentary record and several microfossil groups from two boreholes, with a focus on new records of fish otoliths, Bolboforma and Charophyta. The biostratigraphic evaluation of these groups provides evidence for a position of the Rupelian/Chattian boundary within the upper Niederroedern Formation. This is contrary to the results from a previous sedimentological approach, which places the boundary at the base of the Niederroedern Formation. The fish fauna indicates a biogeographic relation to southern France, the Molasse Basin of Switzerland and southern Germany.

An expanded lower Eocene shelf sequence from the eastern Aquitaine Basin, SW France: biostratigraphy, biofacies, and stable carbon and oxygen isotopes

The early Eocene is characterized by a succession of orbitally-controlled global stable carbon isotope excursions, with some being linked to climatic and related biotic perturbations. The impact of these isotopic excursions has been primarily studied in deep-sea sections under comparably stable conditions. In order to investigate the impact of global post-PETM isotopic signals on shallow marine settings, the Ypresian neritic ʻBlue Marls’ of the Corbieres (SW France) were investigated. High-resolution records of microfossil biota and stable carbon and oxygen isotopes pinpoint biostratigraphic, paleoecologic and geochemic constraints. Calcareous nannofossil biostratigraphy positions the sequence in the upper part of zone NP11, possibly ranging into basal NP12, which is conformable with larger benthic foraminifera data indicating shallow benthic zone SBZ8. This implies a time span of about 0.4 Myr and high overall sedimentation rates of about ~ 32 cm/kyr for the section. A shallowing upward trend from outer neritic to coastal settings is observed in the development of the lithostratigraphy and the microfossil assemblage. The assemblages can be subdivided in seven larger biofacies and four ostracod assemblage zones. The lower third of the section is characterized by strongly fluctuating and partly high plankton/benthos-ratios for neritic settings. A final pronounced peak in plankton occurrence is associated with strong decrease of benthic biota, suggesting anoxic conditions in the outer neritic environment. Several local negative δ13C- and δ18O-excursions can be identified in the section. The upper, most pronounced and consistent negative δ13C excursion is tentatively linked to global carbon isotope excursion K (ETM3) based on the biostratigraphic constraints.

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

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 Süsswasserkalk) and Vectensis Zone (lower Tuberculata Superzone, Oberdorf Süsswasserkalk, 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 Conglomérat de Porrentruy) and Major Zone (Conglomérat 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).

A REVISED PALAEOGENE LITHOSTRATIGRAPHIC FRAMEWORK FOR THE NORTHERN SWISS JURA AND THE SOUTHERN UPPER RHINE GRABEN AND ITS RELATIONSHIP TO THE NORTH ALPINE FORELAND BASIN

The Palaeogene deposits in the Swiss Molasse Basin, the intermediate Swiss Jura and the adjacent southern Upper Rhine Graben represent an excellent case study for interbasinal sedimentary and palaeogeographic relationships. The topographic and geologic complexity of the area led to an accumulation of local stratigraphic terms during nearly 200 years of research activity, necessitating a simplification of the lithostratigraphic framework. Additionally, the extension of the investigated area over two historically shifting language areas and the absence of a standardised supraregional lithostratigraphy adds to complexity of the situation. In revising and grouping around 200 multilingual Palaeogene lithostratigraphic terms and spellings from the northern Jura and the southern Upper Rhine Graben that accumulated since 1821 we propose a concise standardised framework of 10 formations (6 new and/or emended) and 6 new members. It avoids the confusing multitude of historic “formation” names and stratigraphic ambiguity like the “Septarienton”, “Molasse alsacienne” or the “Cyrenenmergel”. The new formations include the Turckheim Formation (formerly “Steingang”, “Conglomerats cotiers”), the Rossemaison Formation (formerly “Terre jaune”, “Gelberde”), the Pulversheim Formation (formerly “Melettaschichten”) and the Wahlebach Formation (formerly “Cyrenenmergel”, partim “Molasse alsacienne”). The Wallau and Hochberg subformations are emended and elevated to formation status. For all discussed units except the Siderolithique new reference and/or type sections are provided and illustrated. This new framework is put in context to recent stratigraphic schemes from adjacent areas in the Upper Rhine Graben, proposing status changes and emendations for existing units (e.g. Wallau-Subformation emended to Wallau Formation). To illustrate the former complexity and the proposed standardisation in the larger area, we applied the lithostratigraphic context to 9 palaeogeographic maps. New heavy mineral data from the Delemont Basin complements the scarce regional information and is discussed in relation to Palaeogene tectonosedimentary context of the North Alpine Foreland Basin and the southern Upper Rhine Graben.

A tribute to the late Professor Jean-Pierre Berger (8 July 1956–18 January 2012)

Professor Jean-Pierre Berger joined the Fribourg University (Switzerland) in 1989 as a lecturer (charge de cours), quickly rising to the rank of head assistant with a postdoctoral lecture qualification in 1992, and becoming Associate Professor for palaeontology in 1997. Fribourg, Lausanne, Tubingen and Munich were important places in his professional career. From the beginning, his scientific interests encompassed a broad variety of topics. He started his career as a biostratigrapher, palaeobotanist and quickly became a renowned specialist for Cenozoic charophytes. Until 2003, he was coordinator of the Group of European Charophytologists. Apart from his exceptional contributions to taxonomy (Berger 1983a, 1992a, b), Jean-Pierre established and improved the application of charophytes as a tool in biostratigraphic zonation (Berger 1983b, 1986, 1992c, 1999; Riveline et al. 1996), and recognized the outstanding importance of stratigraphy for all Earth Sciences-related disciplines. This approach led him to his second research focus, building supra-regional fine-stratigraphic correlation charts that incorporate the most important fossil groups (Berger 1992c; Berger et al. 2005a), and constructing high-resolution, palinspastic palaeogeographic maps (Berger 1996; Berger et al. 2005b). Later on, Jean-Pierre got also interested in mammals, and together with Damien Becker launched a National Research Foundation project in 2007 on the terrestrial palaeoecosystems of Early Oligocene to the Early Miocene large mammals from Western Europe.