This image of Tassili n’Ajjer National Park, part of the Sahara Desert, is made from multiple observations by the Landsat 7 satellite in the year 2000. It uses a combination of infrared, near-infrared, and visible light to better distinguish between the park’s various rock types: Sand appears in shades of yellow and tan; granite rocks appear brick red; blue areas are likely salts. As the patchwork of colors suggests, the geology of Tassili n’Ajjer is complex.
