The European Space Agency has said that its newly released images from its Mars Express show Nili Fossae, a system of deep fractures in the crust around the Isidis impact basin.
Some of these incisions into the Martian crust are up to 500 m deep and probably formed at the same time as the basin.
It is thought that flooding of the basin with basaltic lava after the impact that created it resulted in subsidence of the basin floor, adding stress to the planet’s crust, which was released by the formation of the fractures.
A strongly eroded impact crater is visible to the bottom right of the image. It measures about 12 km across and exhibits an ejecta blanket, usually formed by material thrown out during the impact.
Two landslides have taken place to the west of the crater. Whether they were a direct result of the impact or occurred later is unknown.
A smaller crater, measuring only 3.5 km across, can be seen to the left of centre in the image and this one does not exhibit any ejecta blanket material. It has either been eroded or may have been buried.
The surface material to the top left of the image is much darker than the rest of the area. It is most likely formed of basaltic rock or volcanic ash originating from the Syrtis Major region.