Microfossils: a tool for dating and reconstructing paleoenvironmental changes and biological evolution

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The objective of this research program is to exploit the unique potential of microfossils for reconstructing past environmental and evolutionary changes during major perturbations to the Earth system. The main focus is to assess the causes and consequences of periods of massive burial of marine organic carbon during the Mesozoic. These intervals, known as Oceanic Anoxic Events (OAEs), represent the main source rock of hydrocarbons that are exploited today. Central to the proposed research is the investigation of the four most prominent OAEs of the Mesozoic (Toarcian OAE and Cretaceous OAE1, 2, and 3). These events are associated with pronounced carbon isotope excursions of >1.5 per mille and elevated rates of biotic extinction and speciation indicating a broad impact on the evolution of Earth's ocean, climate, and biotic system. These OAEs will be studied in a mid- to high-latitude transect from the Canadian Western Interior Seaway (CWIS) to the Atlantic Ocean. These areas hold great potential to shed new light on the formation of OAEs because high latitude regions are so important for controlling the global ocean-atmospheric circulation system. A high resolution bio- and chemostratigraphy will be established, that allows the precise stratigraphic correlation between high and low latitudes sections, which are of utmost importance for the understanding of the processes, the timing, and the spatial extension of OAE formation. Furthermore, well established and new indicators for environmental changes (e.g., productivity) will be applied to reconstruct the paleoenvironmental conditions that led to OAEs. To develop new environmental indicators, the formation of organic rich sediments deposited in the Mediterranean Sea during the Holocene, the sapropel S1, will be analyzed. This sapropel may serve as an ideal example of how anoxic sediments have been formed and provides the potential to develop new paleontological indicators for the reconstruction of OAEs. Moreover, selected microfossil groups will be investigated to assess and quantify evolutionary changes connected with the formation of OAEs in a mid- to high latitudinal transect. This transect will allow to distinguish between evolutionary and ecological trends in microfossils through time.