the Paratethys realm became stratified and turned into a giant anoxic sea.

The western and central Paratethys basins experienced intense tectonic activity and anoxia during the Oligocene and early Miocene and became filled with sediments. Local gypsum and salt evaporitic basins formed in the East Carpathian region during the early Miocene. The Eastern Paratethys basin, holding most of the water