Enregistrement par les diatomées des variations paléoenvironnementales durant le Sarmatien dans l’aire paratéthysienne (Roumanie)

This paper is a detailed study based on Sarmatian (Middle Miocene) diatom assemblages, characterized by high biologic productivity and diversity from the Zarand Basin (Romania). A total of 240 diatom taxa were identified, leading to the conclusion that successive environmental variations such as changes in palaeosalinity and palaeobathimetry had taken place during this period. Water-level increases are correlated with marine influx based on the presence of boreal or subtropical marine taxa. Each marine-dominated episode is followed by one of continental influence: an isolated system where freshwater taxa are a common occurrence.