Gypsum tufa cusps in the former Layla Lake
In the center of Saudi Arabia, near the town of Laya, a chain of lakes existed until the 1980ies, when ground water pumpung run them dry. The lakes are situated in very large sinkholes, caved-in atop an Jurassic anhydrite formation. The lake water was saturated with gypsum that precipitaed in the form of these upward growing cusps. Since the lake fell dry, sand is drifting in, its ripples accentuated by streaks of white gypsum.
Stephan Kempe (distributed via imaggeo.egu.eu)