The transition between highlands and lowlands at Nili Fossae
The transition between highlands and lowlands at Nili Fossae
The dichotomy boundary – the transition between the Martian highlands and the lowlands of the northern hemisphere was worn away by erosion over time, resulting in the landscape that we see today, with its strikingly varied and deeply scored surface. The highland plateau, at around 2000 to 3000 metres high, was altered by ice, water and wind, and in places by volcanic and tectonic activity – forces from inside the planet. Water flowing towards the north eroded the edge of the terrain and created the free-standing inselbergs or outliers, as well as the hills found in the foreland. Wind carried volcanic sand and dust into the resulting valleys and depressions in the northern foreland (north is to the right in this image). The contrast has been increased in some of the colour channels to allow us to better make out the details on the Martian surface, so that the dark dust and sand sediments appear dark blue in places.
