An imprint of the Mediterranean middle Miocene circulation pattern in a satellite sea during the Langhian: A case study from the Carpathian Foredeep (Central Paratethys)
Abstrakt
The Langhian Central Paratethys sea represents a unique marine environment with a complicated circulation pattern influenced by the Mediterranean Sea. Here we present a review study based on previously published stable isotopic, foraminiferal and calcareous nannoplankton data from various locations in the Central Paratethys, supplemented by new datasets, from the interval of similar to 14.6-13.9 Ma.
We compared the Paratethyan data with data reported from the Mediterranean area, together with the results of computer models and with the latest paleogeographical studies. As a tool for comparison of particular water masses, we chose delta O-18 data from various benthic and planktonic foraminiferal species (Globigerinoides trilobus, Globigerina bulloides, Cibicidoides spp.) to obtain information for both surficial and bottom waters hydrography.
Moreover, we chose delta C-13 data as an indicator of the relationship between the surficial and bottom waters at particular localities. The composition of foraminiferal and calcareous nannoplankton assemblages was used to verify the paleoecological situation at the studied localities.
It was discovered that an anti-estuarine circulation regime was the basic circulation pattern during the studied interval. This is supported by a similarity in hydrography of surficial waters (surface mixed layer) between the Paratethys and the Mediterranean Sea, which is shown by the isotopic data.
Nevertheless, the isotopic data comparison revealed differences regarding the bottom waters, pointing to an existence of the Paratethyan bottom waters and a subsequent change in the bottom waters isotopic composition between similar to 14.4-13.9 Ma. This change could be linked with the shallowing of the basin that is indicated by various paleobiological data.
Furthermore, we tried to summarize possible regional consequences of the suggested paleocirculation patterns.