Lenz, O. K. ; Wilde, V. ; Riegel, W. (2019)
The Early Eocene of Schöningen - Testing effects of climate variations on coastal wetlands under greenhouse conditions.
Geo Münster 2019. Münster, Germany (22.09.2019-25.09.2019)
Konferenzveröffentlichung, Bibliographie

Kurzbeschreibung (Abstract)

The Helmstedt Lignite Mining District is situated within the Paleogene Helmstedt Embayment, which represented the mouth of an estuary opening towards the Proto-North Sea between uplifts corresponding to the actual Harz Mountains in the South and the Flechtingen Rise in the North. Due to the interaction between changes in sea level, salt withdrawal in the subsurface and climate-related changes in runoff from the hinterland the area of Helmstedt and Schöningen was subject to frequent changes between marine and terrestrial conditions, repeatedly leading to peat formation. Today, a more than 200 m thick lignite-bearing Paleogene succession is limited to two marginal synclines accompanying a more than 70 km long salt wall. The position of the lignites and two major marine transgressions at Schöningen suggested a subdivision of the Paleogene strata from bottom to top in the underlying sediments of the Waseberg Formation, the Lower Eocene Schöningen Formation, the Emmerstedt Formation, the Middle Eocene Helmstedt Formation and the overlying fully marine strata of the Annenberg-, Gehlberg-, und Silberberg Formations. The conventional age model for the coal-bearing part of the Paleogene succession of the Helmstedt Mining District is mainly based on scattered radiometric ages from glauconites and biostratigraphic data from nannoplankton. More recent results from our quantitative studies of the dinoflagellate cyst Apectodinium and carbon isotopes from the reference section at Schöningen indicate that the lowermost part of the Schöningen Formation may still be of Paleocene age.

The marine-terrestrial transitional section at Schöningen is worldwide unique due to its completeness in time from the uppermost Paleocene into the middle Eocene. This presents a unique opportunity for studying terrestrial biodiversity and climate across more than 10 million years including the Early Eocene Climatic Optimum (EECO) and its initial decline with some of the major climatic excursions, such as, e.g., the Paleocene-Eocene Thermal Maximum (PETM). It is the aim of an ongoing project to study trends in the composition of the vegetation and in plant diversity in this paralic environment across the EECO and its gradual demise by making use of pollen and spores as proxies. However, not only the long-term climate trend, but also short-term climatic perturbations such as the PETM and the Eocene Thermal Maximum 2 (ETM-2) and its effects on the vegetation can be studied.

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