Physical and biological properties of the late Miocene, long-lived Turiec Basin, Western Carpathians (Slovakia) and its paleobiotopes

Abstract

International audienceThe Turiec Basin (TB) of Slovakia formed in the Miocene when the West Carpathians escaped from the Alpine region. The 1,250-m-thick sedimentary Neogene fill of the basin preserved fossil leaves as well as endemic bivalves, gastropods, and ostracodes. The paleolimnologic changes recorded in the TB infill were derived from the most abundant fossils, the ostracodes. Five contemporaneous ostracode assemblages within the Late Miocene lacustrine system were distinguished through statistical analysis. These assemblages have low species similarity, between 2.1 and 24.1%, and are recognized by shape differences among the Candoninae. The ostracode assemblages, mollusca fossils, and Sr-isotope ratios suggest a low-salinity environment at the beginning of the Late Miocene, during a brief connection with the Central Paratethys. When the connection ceased, the basin became an isolated freshwater lake, with five zones differentiated ecologically and bathymetrically using the ostracode assemblages. Taxonomic comparison of the faunas of the TB and the freshwater to brackish Neogene basins of Europe demonstrates the endemic character of the TB ostracode fauna. The biologic characteristics of the ostracode families, along with the geology of the lake basin, suggest that the longevity of the Late Miocene lake probably exceeded 1 Ma

Upper Miocene endemic lacustrine gastropod fauna of the Turiec Basin: addressing taxonomic, paleobiogeographic and stratigraphic issues

“…The geological history of the Turiec Basin is well understood, supported by data from structural geology, sedimentology, paleoecology, geochronology, geophysics, and geomorphology (Buday 1962;Gašparík et al 1974Gašparík et al , 1995Konečný et al 1983;Hók et al 1998;Rakús et al 2005;Kováč et al 2011;Pipík et al 2012;Králiková et al 2014). The basin is a 40 km long and 10 km wide westward-dipping halfgraben system with a sedimentary infill of up to 1200 m thickness.…”

“…It de- Kováč et al 2011;Pipík et al 2012). Grey areas display larger villages, filled circles the localities mentioned in the text.…”

“…Most of the known freshwater biota, including the herein presented molluscs, derives from this unit, reflecting the deposits of an isolated freshwater lake. On the basis of the rich ostracod assemblages Pipík et al (2012) defined six paleoecological communities, allowing the ecological and bathymetrical zonation of Lake Turiec during the Late Miocene. Rapid uplift of the surrounding mountain chains during the latest Miocene and Early Pliocene resulted in the deposition of alluvial fans along the western, southwestern, and northwestern basin margins.…”

“…Some genus names deriving from published as well as unpublished data were mentioned by Kováč et al (2011) and Pipík et al (2012), namely Viviparus, Theodoxus, Melanopsis, Hydrobia, Pyrgula, Lymnaea, Ancylus, Gyraulus, Planorbis, Kosovia, Congeria, Unio, and Anodonta. Especially the record of the genus Kosovia was eye-catching, since it is a known endemite for basins in Kosovo and southern Serbia. Krstić et al (2012) determined the species as Kosovia strophostomopsis Milošević, 1965, which was originally described from the Late Pontian (Early Pliocene) of the Metohia Basin.…”

A new Late Agenian (MN2a, Early Miocene) fossil assemblage from Wallenried (Molasse Basin, Canton Fribourg, Switzerland)

“…in fluviatile and spring habitats (e.g., Pieri et al 2009;Janz and Matzke-Karasz 2001). Pipík and Bodergat (2004) and Pipík et al (2012) associate Miocene Psychrodromus with cold freshwater influx into a lake. The unrelated ostracod assemblages indicate different environments for the origin of the material in localities WallA and E. Since the ostracod material in WallA is rather poorly preserved, it may very well be transported over longer distances, whereas the good preservation in WallE suggests an autochthonous deposition or only short transport.…”