Bioturbation structures in the Holovnia Siliceous Marls (Turonian-lower Santonian) in Rybotycze (Polish Carpathians)

The Holovnia Siliceous Marls represent carbonate turbidites interbedded with non-calcareous pelagic/hemipelagic shales. This study reports on bioturbation pattern, trace fossil assemblage and distribution of bioturbation structures, i.e. structures resulting from the life activity of organisms in general, in the succession exposed in the village of Rybotycze. 20 ichnospecies were identified, with one new ichnogenus (Squamichnus) and one new species (Squamichnus acinaceformis). The ichnofossils represent nearly exclusively fodinichnia produced close to the seafloor, below calcite compensation depth. Shallow location of anoxic pore waters is indicated to be responsible for relatively shallow bioturbation depth whereas variability in frequency of turbidite sedimentation and petrographic composition of turbidites is suggested as the chief control on the vertical distribution of the bioturbation structures in the succession.