Babejová-Kmecová J., Plašienková I., Sliva Ľ., Halásová E. & Hlavatá Hudáčková N., 2022: From dysoxic sea to hypersaline lagoon: paleoenvironmental changes on the Badenian/Sarmatian boundary (borehole MZ102; Vienna Basin). Acta Geologica Slovaca, 14, 1, 57–70.

From dysoxic sea to hypersaline lagoon: paleoenvironmental changes on the Badenian/Sarmatian boundary (borehole MZ102; Vienna Basin)

Jaroslava Babejová-Kmecová¹, Ivana Plašienková¹, Ľubomír Sliva², Eva Halásová¹ & Natália Hlavatá Hudáčková¹

¹Univerzita Komenského, Prírodovedecká fakulta, Katedra geológie a paleontológie, Ilkovičova 6, 842 15 Bratislava, Slovenská republika; kmecova45@uniba.sk
²Nafta a.s. 821 09 Bratislava, Slovakia

Abstract

The main objective of this work was to interpret the environment during a very dynamic paleoenvironmental change from the Badenian to the Sarmatian in the Central Paratethys, as well as to determine ecologic factors, diversity, and the relationship between the foraminiferal morphogroups in the northern part of the Vienna Basin. The samples of this study come from the MZ 102 borehole, which had been drilled near the town of Malacky in the northern part of the Vienna Basin (Slovakia) (Fig. 1). Based on sedimentology and fossil occurrence, we interpreted a paleoenvironment of the northern part of the Vienna Basin during the middle Miocene. By examining changes in the occurrence of foraminifera (Articulina sarmatica, Cycloforina stomata, Tenuitella acme) and calcareous nannofossils (Coccolithus miopelagicus) in the studied samples, we detected the position of the Badenian/Sarmatian boundary. Low-oxic conditions in the uppermost Badenian (Studienka Fm.) and upper Sarmatian (Skalica Fm.) sediments were interpreted, as well as fluctuation from a normal marine to hypersaline shallow water paleoenvironment in the middle and upper Sarmatian sediments (Skalica Fm.). Macrofauna was represented mostly by bivalves and gastropods shells and fish remains. Samples were compared with samples from the nearby MZ 93 borehole to fill in the gaps in the MZ 102 borehole record.

Key words: Vienna Basin, Foraminifera, Paleoenvironment, Middle Miocene, Calcareous nannoplankton, sedimentology

Manuscript received: 2022-02-08

Revised version accepted: 2022-06-06