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Christian J. Nyhuis, Fellowship Grant 2014

Prospectivity of black-shale microfacies

Black-shales belong to the most poorly understood sedimentary rock types, especially in NW Europe. The lack of knowledge may be caused by their macroscopic homogeneity, leading to the false conclusion that they are microscopic homogeneous and boring, not worthy of any detailed investigations. Typically, they are regarded as classical examples of hemipelagic quiet water deposits that accumulated under anoxic bottom water conditions through vertical aggradation. For my PhD thesis I investigated Carboniferous black-shales in Germany, the Netherlands, and Belgium by integrating high-resolution core description and thin-section petrography. Complementary tools (e.g. TOC, XRD, SEM, and palaeontology) were used to understand facies patterns and depositional conditions of the investigated rocks better. The financial support provided by Graduate School of Geosciences (GSGS), University of Cologne, enabled me to finish my studies on black-shale microfacies and to publish results. My research demonstrates that, in spite of their macroscopic homogeneity, the investigated rocks are microscopic heterogeneous, independent of their location and stratigraphy. Assumed anoxic conditions cannot be confirmed for the majority of the investigated lithologies. A restricted ichnofabric, indicated among others by Planolites, Teichichnus, and cryptobiodeformational structures, suggests that at least dysoxic conditions were temporarily favored within specific intervals. Moreover, sedimentary features contradict sedimentation by vertical aggradation of fine-grained material. In conclusion the depositional mechanisms causing the formation of the investigated rocks are much more diverse, complex and dynamic, and are often interrelated. These results change our understanding of the complex formation of finegrained deposits in the investigated area. I am sincerely grateful to the Graduate School of Geosciences (GSGS) University of Cologne for this fellowship grant.

Christian J. Nyhuis, Dipl.-Geol.
PhD student

Institute of Geology und Mineralogy

(Arbeitsgruppe Paläontologie und Historische Geologie)