The Cretaceous–Paleogene boundary in the East Carpathians, Romania: evidence from geochemistry, mineralogy and calcareous nannofossils
Published:January 01, 2013
Ana-Voica Bojar, Hans-Peter Bojar, 2013. "The Cretaceous–Paleogene boundary in the East Carpathians, Romania: evidence from geochemistry, mineralogy and calcareous nannofossils", Isotopic Studies in Cretaceous Research, A.-V. Bojar, M. C. Melinte-Dobrinescu, J. Smit
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We performed detailed geochemical, mineralogical and calcareous nannofossils investigations on two Maastrichtian–Paleocene sections situated in the Eastern Carpathians, Romania. One of the sections is situated in the Carpathian bend area, in the Ialomiţa Valley and is composed of red marine hemipelagic sediments. The other section is located in the northern region of the Eastern Carpathians, along Varniţa Brook and consists mainly of turbidites. In both sections, the Cretaceous–Paleogene (K–Pg) boundary is characterized by nannoplankton mass extinction (over 90%) of the Cretaceous nannofloras, followed by blooms of survivor taxa, such as the calcareous dinoflagellate genus Thoracosphaera and the nannofloral species Braarudosphaera bigelowii. In the Ialomiţa section, the K–Pg boundary is marked by a drop in calcite and TOC content, as well as a negative excursion in the δ13C values of organic material. These trends are only partly present in the Varniţa Brook section, where both calcite and TOC content show a decrease, but no negative excursion is seen in the δ13C values of organic material.
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Isotopic Studies in Cretaceous Research
The Cretaceous was a period characterized by very warm climate, oceanic anoxic and oxic events and enhanced volcanic activity. The end of the Cretaceous is punctuated by a well-documented asteroid impact and the extinction of, among other groups, the dinosaurs. This volume elucidates various aspects of Cretaceous marine and continental environmental conditions. The articles in this book present a broad range of interdisciplinary contributions, which are grouped into sections on marine environments(including anoxic and oxic events, volcanism and the Cretaceous–Palaeocene boundary); mixed marine–freshwater environments and continental records. The isotopic data are combined with further geochemical, palaeontological, lithological and mineralogical proxies. The interdisciplinary approach offered here gives a solid investigation base for this fascinating period. There are examples from Europe, Asia, South and North America, and from the Early Cretaceous to the Cretaceous–Paleogene boundary.