Layered Martian terrain. Coloured satellite image of layered rocks in Arabia Terra, northern Mars. The rocks have layers of roughly uniform depth. They were formedwhen environmental conditions repeated at regular intervals, a process known as cyclic bedding. Image obtained by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO) on 24th July 2009. The width of this image is roughly 1.3 kilometres across.