Ubari Sand Sea, Libya. Playa lake in Fezzan. This saline lake at Nashnusha, about 60 kilometers northwest of Umm Al Abyad in the Ubari Sand Sea, dries up in the summer. In the background are the high sand dunes in step from several tens of meters high. To the right of center are the deposits of sodium carbonate in the bottom of the lake. The striped pattern results from troughs dug in the lake to concentrate the sodium carbonate. Circa 1958. Figure 16-B, U.S. Geological Survey Professional Paper 660.
Digital File:ggh00019