6. Dust Storm in Progress, Cerro Galan, Argentina
This photograph shows a dust storm in progress in the vicinity of one of the Earth’s largest volcanic structures. The central peak of the 2.2-million-year-old Cerro Galan caldera (right, center above playa lake) stands about 6600 meters (21,600 feet) high and is one of the highest peaks in northern Argentina. Prevailing winds in this part of the high Andes blow fiercely from the northwest for much of the year, and are responsible for significant eolian modification of landforms. Dust is being entrained from two distinct sites in the photograph. Around the shores of playa lakes such as the Salar Hombre Muerto (top) fine white crystals of gypsum forming from the drying lake are easily picked up by the wind and form the prominent whitish dust plumes.
Easily eroded fine-grained Late Tertiary continental sediments also outcrop in the area, and these contribute a reddish dust. An outcrop of red beds is visible at the bottom of the photograph. Surface areas downwind of source regions are often mantled with windblown dust. The desert surface at the bottom shows the effect of mantling with dust derived from the red beds.
STS-8, August-September 1983. Picture #8-46-0924.