Evolution of organogenic carbonate buildups in the Middle through Late Miocene of the Euxine-Caspian Basin (Eastern Paratethys)

Two types of organogenic carbonate buildups (bryalgal and algal-microbialite) occurring for approximately 11 Ma from the Middle through to the Late Miocene in the Euxine-Caspian Basin are considered. Four main stages in the formation of these structures are established: Chokrakian-Karaganian, Early-Middle Sarmatian, Maeotian, and a specific Late Sarmatian one. Each of the first three stages began with bryalgal bioherms that, during the growing basins’ isolation, transformed into algal-microbialite buildups. Only bryalgal buildups are found in the Late Sarmatian Basin.