Abstract:The Sarmatian sedimentary record of the Borod Depression (eastern Pannonian Basin) consists of a marine sequence with continental influence. The investigated section, located near Vârciorog, was biostratigraphically and paleoenvironmentally analysed. The micro-and macrofossil assemblages include dasycladaceans, characeans, foraminifera, molluscs, polychaetes, ostracods, crabs, bryozoans, fish and vertebrate remains, which are characteristic for a shallow marine setting with local transitions to continental facies. The microfossil assemblages are characteristic for the Elphidium reginum Zone and Mohrensternia Zone of the early Sarmatian (Serravallian). The succession of populations correlates with the sedimentological trend, allowing the separation of several genetic units. The relative sea-level changes and the progradational trend from the top of the section suggest active tectonics in the hinterland (Apuseni Mountains). The shallow seas surrounding the emerging islands (Apuseni Mountains) provided the connections between the Pannonian and Transylvanian basins during the early Sarmatian.Key words: Sarmatian (late Middle Miocene), Borod Depression (NW-Romania), paleoenvironments, paleogeography, sequence stratigraphy, molluscs, bryozoans, foraminifera, ostracods. most representative. Here, we document the micropaleontological record and discuss the detected paleoenvironmental changes in order to restore a part of the paleogeographical evolution at the eastern border of the Pannonian Basin. Material and methodsForty-three samples were collected from fine-grained siliciclastic intervals along the ~9 m thick section, at distances between 5 to 20 cm (Fig. 2). All the samples were processed by standard micropaleontological methods. The microfossils were recovered from the 63 µm sieve fraction after washing 250 g of dried sediment from each sample. Identification of taxa was followed by quantitative analyses of foraminifera based on percentage distribution of different groups (Fig. 4). Representative taxa are documented by stereomicroscope and the scanning electron microscope (SEM) photographs inserted in Figures 5 to 10. ResultsThe microfossil assemblages were interpreted from the biostratigraphic and paleoecological points of view, trying to point out their relationship to the relative sea-level changes

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Abstract:The Sarmatian-Pannonian transition has been investigated in Section A of Oarba de Mure in the central Transylvanian Basin. Micropaleontological assemblages are diagnostic for different environmental settings and demonstrate a clear zonation, which was used to reconstruct the genetic units. Five stratigraphic sequences were described and subdivided based on the microfossil assemblages. Transgressive intervals were documented by five-chambered and biserial planktonic foraminifera, normal regressions by assemblages with abundant mysid, dasyclads, diatoms, and benthic rotaliid foraminifera, while the forced regressions are characterized by reworking. The Sarmatian-Pannonian boundary (11.3 Ma) is clearly documented by microfossils and is calibrated with radiometric and magnetostratigraphic data. A new interpretation for the interbasinal correlation is proposed by synchronizing the top of the Central Paratethyan Sarmatian with the top of the Eastern Paratethyan Bessarabian.

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The late middleMiocene microfossil assemblages from the easternmost Pannonian Basin in Romania preserve numerous evolute and deformed specimens of Elphidium, which are assigned to the Recent species E. tongaense (Cushman 1931) originally described from the Pacific. Ourmaterial suggests that the origin of the species is back in the middle Miocene, when amarine connection between the Paratethys and the Indo-Pacific regions probably existed.