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.
Trans-Caspian Gas Pipeline
The project is heavily criticized by Russia and Iran, current transit countries for Turkmen gas. Alexander Golovin, special envoy on Caspian issues, has stated that a major gas pipeline would pose a serious, dangerous risk to the prosperity of the entire region. According to the Russian Natural Resources Ministry, any gas or oil pipelines across the floor of the Caspian Sea would be environmentally unacceptable. Russia has also taken the legal position that a potential pipeline project, regardless of the route it takes on the seabed, would require the consent of all five Caspian littoral states in order to proceed. Iran has pointed out that treaties signed by Iran and the Soviet Union in 1921 and 1940 are still in force and that any action taken without the consent of all the littoral states would be illegal. In regard of the decision taken by the EU on 12 September 2011, Russia expressed its "disappointment" as it "seems to have been adopted without taking into account the internationally accepted legal and geopolitical situation in the Caspian basin," and as Caspian Sea littoral state, Russia could veto any international agreement allowing for the pipeline to be built.