Cretaceous-Paleogene Boundary Sequence in the Bukovec Section, Outer Flysch Carpathians.

Outer Flysch Carpathians in Czech Republic can provide valuable information on Cretaceous-Paleogene (K-Pg) boundary events in the sub-CCD sediments of the deep-sea basins. We are carrying out multidisciplinary research to study the local magnetic, biotic, geochemical, and paleoenvironmental variations. One of the studied localities, Bukovec section (BU) at the Czech-Polish border, consists of isolated outcrops of the Upper Maastrichtian - Lower Paleocene strata of the Silesian Unit. Section is dominated by dark silty mudstones which are influenced by influx of organic matter from North-European continental margin. Fossil record encompasses dinoflagellate cysts, agglutinated foraminifers, pyritized radiolarians and diatoms. The paleo- and rock magnetic research indicates that mostly small amount of magnetite contributes to low magnetic susceptibilities (on average MS <300 SI) and natural remanent magnetization (0.34 mA/m) in mudstones of both Upper Cretaceous and Lower Paleocene outcrops. Traces of high coercivity minerals were also detected. Only low amount of superparamagnetic particles (frequency dependence of magnetic susceptibility FD 0-3%) was observed in most of the outcrops, with exception of the Lower Paleocene mudstones in outcrop BU15 which indicated FD >8 %. Mercury (Hg) content varies considerably (8 221 ppb) with maximum values located at the base of BU15. Magnetic (e.g. IRM coercivity distribution of the magnetic mineral phases, temperature dependence of MS, magnetostratigraphy), paleontological (biostratigraphy) and geochemical (e.g. total organic carbon and total sulphur to evaluate the primary host phase of Hg) analyses of Bukovec section are still in progress. The research is supported by Czech Science Foundation project 19-07516S and is in accordance with research plan no. RVO67985831.