ESA's Mars Express orbiter has captured spectacular images of the northern hemisphere of the Red Planet, and found evidence of some ancient tectonic activity.

The area is in the western part of Acheron Fossae, a region that is 800 kilometers (500 miles) in length, 280 kilometers (175 miles) in width, and stands 2 kilometers (1.2 miles) above the surrounding lands.

The region, snapped in May 2016, is believed to be an example of a geological feature known as horst and graben, where underground movements create elongated fault blocks that have been raised and lowered respectively. On Earth, this process has created areas like Death Valley and the Dead Sea, as well as many others.

Cross-cutting faults, which seem to originate from different directions, are also found in the region – an indication that the area has a geological history formed by powerful activities.

The Acheron Fossae region is believed to be related to the fractures that originated from the major volcanic area of Mars: the Tharsis region. This area houses three volcanos and Olympus Mons, an extinct volcano three times the height of Everest and as wide as France.

^{Topography of the western Acheron Fossae. ESA/DLR/FU Berlin} 

The images also show a large curved ridge that might be an ancient valley, which over time was filled with material flowing into it. The climate was very different when this region settled in its current configuration.

Geological analysis suggests that these fractures formed between 3.7 and 3.9 billion years ago. At the same time, the Tharsis region was bulging with hot material rising from the depths of Mars. The swelling caused the Martian crust to crack, producing the features seen in Acheron Fossae.

Mars is not geologically active anymore, at least majorly, so studying these features allows scientists to examine the evolution of the Red Planet’s crust and interior.