The evolution of the Carpathian Foredeep Basin during the latest Badenian and Sarmatian (Middle Miocene): inferences from micropalaeontological data

Abstract

Seven Middle Miocene (Upper Badenian to Lower Sarmatian) sedimentary sections of the Central Paratethys, two from the Polish Carpathian Foredeep Basin (PCFB) and five from the Eastern Carpathian Foreland Basin (ECFB) of Romania and the Republic of Moldova have been analysed micropalaeontologically to better constrain the Badenian-Sarmatian Extinction Event, characterized by significant taxonomic impoverishment of both foraminifers and ostracods. Our studies show significant palaeoenvironmental changes in the basin including depth, salinity, oxygenation, and organic matter flux. The occurrence of moderately diverse planktonic foraminifera (Globigerina, Globigerinita, Globorotalia, Trilobatus, Orbulina, Velapertina) in the Upper Badenian deposits of the PCFB as well as in the ECFB and their rarity in the lowermost Sarmatian indicate an almost fully marine environment during the latest Badenian, followed by a significant regression and possible appearance of much more restricted marine conditions across the boundary. The taxonomic composition of the Sarmatian foraminifera, ostracoda and calcareous nannofossils indicate that during this interval the salinity fluctuated strongly, with the water regime varying from brackish to normal marine. In addition, the identified micropalaeontological assemblages identified show palaeoenvironmental similarity across different basins of the Central Paratethys. This supports a hypothesis of possible connections during the latest Badenian between different areas of the Central Paratethys, as well as of the existence of a gateway between the Central Paratethys and the Mediterranean realm

Foraminiferal and Palynological Records of an Abrupt Environmental Change at the Badenian/Sarmatian Boundary (Middle Miocene): A Case Study in Northeastern Central Paratethys

“…The next almost monospecific assemblage (assemblage IX), which is dominated by Anomalinoides dividens, probably reflects a salinity lowering to normal marine values. Presently, marine environments are characteristic for Anomalinoides [79], although in the past, its wider environmental range, including brackish salinity conditions, was accepted [46] (with references therein).…”

Evidence of the middle Miocene paratethys transgression from Jurkowice-Budy site (SE Holy Cross Mountains, Poland

“…1) and became a peripheral foreland basin. The palaeo-environmental conditions of the Paratethys varied considerably under the influence of temporary connections with the Mediterranean and the Indo-Pacific realms (Dumitriu et al 2020). The Paratethys basin was a system of associated inland seas periodically subjected to partial or complete isolation from open sea waters (Kováč et al 2017;Sant et al 2017).…”