Deserts

Inside the curve of the Helmand River are two deserts: Dasht-i Margo, which overlies the alluvial fill and Tertiary lakebeds of the Helmand Basin; and Dasht-i Jehannum, located between the Sar-o-Tar Plain and the Helmand River. These deserts are severely wind eroded and covered with a layer of dark gravels and cobbles eroded from the mountains to the north. The Sistan Depression has been excavated by various natural forces over 200 m below the Dasht-i Margo. Habitation in this desert region is limited to stream and river valleys and the basin floor of Sistan where water can be procured. To the east and south is the Registan, “land of sand,” which is primarily stabilized sand dunes, some as much as 75 m high, pushed together by the Sistan winds.