As the astronauts on the International Space Station passed over the deserts of central Iran recently, they were greeted by this striking pattern of parallel lines and sweeping curves. The lack of soil and vegetation in the Kavir desert (Dasht-e Kavir) allows the geological structure of the rocks to appear quite clearly. The patterns result from the gentle folding of numerous, thin layers of rock. Later erosion by wind and water cut a flat surface across the dark- and light-colored folds, not only exposing hundreds of layers but also showing the shapes of the folds. The pattern has been likened to the layers of a sliced onion.
The dark water of a lake (image center) fills a depression in a more easily eroded, S-shaped layer of rock. The irregular, light-toned patch just left of the lake is a sand sheet thin enough to allow the underlying rock layers to be detected. A small river snakes across the bottom of the image. In this desert landscape, there are no fields or roads to give a sense of scale. In fact, the width of the image is about 105 kilometers (65 miles).