Caspian Sea
The Caspian Sea, like the Black Sea, Namak Lake, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level. During warm and dry climatic periods, the landlocked sea almost dried up, depositing evaporitic sediments like halite that were covered by wind-blown deposits and were sealed off as an evaporite sink when cool, wet climates refilled the basin. (Comparable evaporite beds underlie the Mediterranean.) Due to the current inflow of fresh water, the Caspian Sea is a freshwater lake in its northern portions, and is most saline on the Iranian shore, where the catchment basin contributes little flow. Currently, the mean salinity of the Caspian is one third that of Earth's oceans. The Garabogazköl embayment, which dried up when water flow from the main body of the Caspian was blocked in the 1980s but has since been restored, routinely exceeds oceanic salinity by a factor of 10.
Eemian Sea
The Eemian Sea was a body of water located approximately where the Baltic Sea is now during the last interglacial, or Eemian Stage, Marine isotopic stage (MIS) 5e, roughly 130,000 to 115,000 years BP. Sea level was 5 to 7 metres higher globally than it is today, due to the release of glacial water in the early stage of the interglacial. Although “Eemian” rightly applies only to the northern European glacial system, some scientists use the term in a wider sense to mean any high-level body of water in the last interglacial.
The early Eemian Sea connected with the White Sea along the line of the present White Sea-Baltic Canal. Karelia was inundated and Lakes Ladoga and Onega were mere depressions in the shallow eastern end of the Eemian sea. At the other end the sea connected to the North Sea more broadly than its presently does. Much of northern Europe was under shallow water. Scandinavia was an island. The salinity of the Eemian Sea was comparable to that of the Atlantic. Scientists reach these conclusions from a study of types of micro-organisms fossilized in the clay sediments laid down in the Eemian Sea, and from the included pollen of "Corylus", "Carpinus" and "Betula".