The Middle Zarafshan natural-geographic district

The Middle Zarafshan district lies in the centre of Uzbekistan, in the middle part of the Zarafshan valley that belongs to the republic. It has clear natural boundaries: the Nurata mountains in the north, the Chakilkalon, Karatepa, Zirabulak and Ziyovuddin mountains in the south, Tajikistan in the east; in the west the Khazar corridor separates it from the Lower Zarafshan district. The district lies in a sunken part of the Turan plate; in the Neogene it became land from sea sediments, then the river deepened its channel and made several floodplain terraces. The surrounding mountains are of Paleozoic limestone, crystalline rock and shale, raised in the Hercynian folding. The valley falls from east to west: 700–750 m near Samarkand, 450 m at Kattakurgan, 347 m at Navoi. The highest peak of the Nurata range is Hayotboshi, 2169 m. The valley alternately widens and narrows; the Samarkand depression stretches about 220 km west to the Khazar corridor and is 50–60 km wide. In the Khazar corridor the valley narrows to 8–10 km. Soft loess-like rock has been cut by streams and seasonal water into many gullies.