ESA Mars Express observes clusters in Ares Vallis

A wider contextual image of the region surrounding Oraibi crater in Ares Vallis. The smaller rectangle shows the region covered in this Mars Express HRSC image release.

Credits: ESA/DLR/FU Berlin (G. Neukum)

The great outflow that partially eroded Oraibi also cut stepped riverbanks and excavated parallel channels in the riverbed that indicate the flow path.

Streamlined islands have been left standing above the valley floor, again indicating the direction taken by the flow.

On the floor and on the plateau to the left of the image there are a number of ‘ghost craters’.

These were once fully formed craters, but water or wind eroded their rims and filled them by depositing sediments.

Their presence on the plateau suggests that even that higher ground may have been at least partially overrun by flooding.

The solitary mounds that can be seen likely represent the remaining sections of the plateau’s original surface.

Read more at ESA Mars Express Portal