The
Caspian Sea is the largest enclosed body of water on
Earth by area, variously classed as the
world's largest lake or a full-fledged
sea.
[2][3] It has a surface area of 371,000
square kilometers (143,244&_160;
sq&_160;mi) and a volume of 78,200
cubic kilometers (18,761&_160;cu&_160;mi).
[4] It is an
endorheic body of water (has no outflows), and lies between the southern areas of the
Russian Federation and northern
Iran. It has a maximum depth of about 1025 meters (3,363 ft).
It was perceived as a sea by its ancient coastal inhabitants because it is salty and seemed boundless. It has a salinity of approximately 1.2%, about a third the salinity of most seawater. According to Strabo, it is named after an ancient people called Caspians.[5]
Like the Black Sea and the Mediterranean, the Caspian Sea is a remnant of the ancient Tethys Ocean. It became landlocked about 5.5 million years ago due to continental drift. During warm and dry climatic periods, the landlocked sea has all but dried up, depositing evaporitic sediments like halite that have become covered by wind-blown deposits and were sealed off as an evaporite sink,[6] when cool, wet climates refilled the basin.[7] Due to the current inflow of fresh water, the Caspian Sea is a fresh-water lake in its northern portions. It is more saline on the Iranian shore, where the catchment basin contributes little flow. Currently, the mean salinity of the Caspian is one third that of the Earth's oceans. The largely dried-up Garabogazköl embayment routinely exceeds oceanic salinity.[8]
The Caspian Sea is the largest inland body of water in the world and accounts for 40 to 44 percent of the total lacustrine waters of the world. The coastlines of the Caspian are shared by Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The Caspian is divided into three distinct physical regions Northern, Middle, and Southern Caspian.[9] The North-Middle boundary is the Mangyshlak threshold, which runs through Chechen Island and Cape Tiub-Karagan. The Middle-South boundary is the Apsheron threshold, a sill of tectonic origin[10] that runs through Zhiloi Island and Cape Kuuli.[11]
