Martian landscape. Infrared and visible light composite image showing the region south of the Mawrth Vallis on Mars. This and the Mawrth Vallis area hold special interest because of the presence of phyllosilicate minerals. These phyllosilicates (orange), which are compounds similar to Earth's iron-rich clays, are thought to have formed during a time when water flowed on the now arid planet. Image taken on 1st October 2006 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO).