Deciphering shallow marine ecosystem dynamics during rapid global warmings: an early Eocene North Sea Basin perspective (Belgium).

The early Eocene climate history (56 to 50 Ma ago) displays a suite of rapid global warming events, the so-called hyperthermals. This research project aims for the first time at deciphering the impact of these events in the shallow marine environments of the North Sea Basin. The first objective provided a firm stratigraphic framework and geological age model for the lower Eocene clays at Kallo, which was needed as the basis for detailed paleoenvironmental reconstructions. Therefore, high-resolution isotopic (δ13C) and biotic (qualitative distribution patterns of marker taxa) records were generated to reveal the exact position of the hyperthermals. The second objective is to investigate the sequence of depositional and environmental changes through the combination of biotic (quantitative distribution pattern of microfossils) and geochemical proxies (paleoredox, paleoproductivity and paleothermometry). The obtained results help to understand the overall impact of global warming in shallow marine environments as well as evaluating ecosystem dynamics under a range of temperature anomalies.