Caspian Sea

The Caspian Sea lies to the east of the Caucasus Mountains and to the west of the vast steppe of Central Asia. The sea’s name derives from the ancient Kaspi peoples, who once lived in Transcaucasia to the west. Among its other historical names, Khazarsk and Khvalynsk derive from former peoples of the region, while Girkansk stems from Girkanos, “Country of the Wolves.”

The elongated sea sprawls for nearly 750 miles (1,200 km) from north to south, although its average width is only 200 miles (320 km). It covers an area of about 149,200 square miles (386,400 square km)—larger than the area of Japan—and its surface lies some 90 feet (27 metres) below sea level. The maximum depth, toward the south, is 3,360 feet (1,025 metres) below the sea’s surface. The drainage basin of the sea covers some 1,400,000 square miles (3,625,000 square km). The sea contains some 63,400,000,000 acre-feet or 18,800 cubic miles (78,200 cubic km) of water—about one-third of Earth’s inland surface water. The sea is bordered in the northeast by Kazakhstan, in the southeast by Turkmenistan, in the south by Iran, in the southwest by Azerbaijan, and in the northwest by Russia.

The Caspian is the largest salt lake in the world, but that has not always been true. Scientific studies have shown that until relatively recent geologic times, approximately 11 million years ago, it was linked, via the Sea of Azov, the Black Sea, and the Mediterranean Sea, to the world ocean. The Caspian is of exceptional scientific interest, because its history—particularly former fluctuations in both area and depth—offers clues to the complex geologic and climatic evolution of the region. Human-made changes, notably those resulting from the construction of dams, reservoirs, and canals on the immense Volga River system (which drains into the Caspian from the north), have affected the contemporary hydrologic balance. Caspian shipping and fisheries play an important role in the region’s economy, as does the production of petroleum and natural gas in the Caspian basin. The sea’s splendid sandy beaches also serve as health and recreation resorts.

The Caspian basin, as a whole, is usually divided into the northern, middle, and southern Caspian, based partly on underwater relief and partly on hydrologic characteristics. The sea contains as many as 50 islands, most of them small. The largest are Chechen, Tyuleny, Morskoy, Kulaly, Zhiloy, and Ogurchin.

The shores of the northern Caspian are low and reflect the great accumulation of alluvial material washed down by the Ural, Terek, and, above all, Volga rivers, whose deltas are extensive. The western shore of the middle Caspian is hilly. The foothills of the Greater Caucasus Mountains loom close but are separated from the coast by a narrow marine plain. The Abşeron Peninsula, on which the city of Baku is sited, thrusts out into the sea there, while just to its south the floodplain of the Kura and Aras rivers forms the Kura-Aras Lowland along the western shore of the southern Caspian. The southwestern

and southern Caspian shores are formed of the sediments of the Länkäran and Gīlān-Māzanderān lowlands, with the high peaks of the Talish and Elburz ranges rearing up close inland.

Britannica