The Lower Zarafshan natural-geographic district

The Lower Zarafshan district lies in the lower part of the Zarafshan river and includes the Bukhara and Karakul oases. In the east the 8–10 km wide Khazar corridor separates it from Middle Zarafshan; it borders Kyzylkum in the north and west, Turkmenistan across the Sandykli sands in the south-west and the Kashkadarya district in the east (along the Azkamar, Kuyimazar and Jarkak uplands). The district lies in a tectonic depression: Mesozoic and Cenozoic sediments cover Paleozoic rock, and the most widespread are Quaternary gravel, sand, loam and loess. In the past the Kashkadarya and Sangzor flowed into the Zarafshan; when they turned away, the Zarafshan lost water, formed the Karakul delta and no longer reached the Amudarya. The surface differs from Middle Zarafshan: it is not ringed by mountains and after the Khazar corridor it widens and falls to the south-west. The Bukhara oasis is about 102 km long and 50–70 km wide at 200–250 m; the Karakul oasis is about 100 km long and 50 km wide at 178–200 m. Neotectonic movements cause earthquakes (strong ones at Gazli in 1976 and 1984). Oil and gas fields: Gazli, Jarkak, Karaulbazar, Shodi, Dengizkul.