Caspian Sea and a Pleistocene stage, that includes glaciation cycles and the creation of the present Volga River. During the first stage, the Tethys Sea had evolved into the Sarmatian Lake, that was created from the modern Black Sea and south Caspian, when the collision of the Arabian peninsula with Western Asia pushed up the Kopet Dag and Caucasus Mountains, setting definitive south and west boundaries to the Caspian basin. This orogeneic movement was continuous throughout the years, while Caspian was regularly disconnecting from the Black Sea. In the late Pontian, a mountain arch rose across the south basin and divided it
Black Sea of the Black Sea reaches a maximum depth of just south of Yalta on the Crimean Peninsula. The littoral zone of the Black Sea is often referred to as the Pontic littoral or Pontic zone. The area surrounding the Black Sea is commonly referred to as the "Black Sea Region". Its northern part lies within the "Chernozem belt" (black soil belt) which goes from eastern Croatia (Slavonia), along the Danube (northern Serbia, northern Bulgaria (Danubian Plain) and southern Romania (Wallachian Plain)) to northeast Ukraine and further across the Central Black Earth Region and southern Russia into Siberia. The Black Sea