Palynofacies around the Frasnian/Famennian boundary in the Holy Cross Mountains, southern Poland

Palynofacies have been analysed in two representative Frasnian/Famennian (F/F) localities (Kowala Quarry and Łagów-Płucki trench) in the Holy Cross Mountains, Poland, with the aim of reconstructing sedimentary conditions and palynofloral history over the extinction boundary interval. Leiospheres are the most common palynomorphs. Taxonomically impoverished acritarch assemblages and a low proportion of land-derived material indicate offshore sedimentation in a mid-shelf environment, with some evidence of an earliest Famennian regression. Increased productivity of phytoplankton near the F/F boundary was possibly related to eutrophication of the epeiric seas, thus causing anoxic conditions close to and on the seafloor. No significant changes in palynofacies have been observed through the F/F boundary deposits in these Laurussian shelf basins, in agreement with data from other parts of the Devonian world.