Turfan Depression

a tectonic basin in West China, in the foothills of the eastern Tien-Shan. It is approximately 200 km long and 70 km wide and reaches a depth of 154 m below sea level, the lowest point in Central Asia. The depression is composed primarily of Mesozoic and Cenozoic sandy-argillaceous deposits. At the bottom of the depression is a vast solonchak containing an ephemeral bitter lake. The climate is extremely continental, with hot summers (mean July temperature, 33°C; maximum, 47.6°C) and cold winters (mean January temperature, –9.6°C). Annual precipitation totals approximately 20 mm. Vegetation, including the niterbush and the camelthorn, grows only along the channels of seasonal water courses. There are oases with karez (underground) irrigation. The city of Turfan is in the Turfan Depression. The first European to describe the depression was the Russian geographer G. E. Grumm-Grzhimailo in 1889.