At first glance, these features look as if someone has raked their fingernails across the surface of the Red Planet, gouging out lengthy trenches as they did so.

While not quite so dramatic in its formation, Tantalus Fossae (‘fossae’ meaning a hollow or depression) is a noticeable feature on Mars. This system of troughs flanks a sprawling, low-relief martian volcano named Alba Mons, running along the volcano’s eastern side.

The fossae were created as the summit of Alba Mons rose in elevation, causing the surrounding surface to become warped, extended and broken. The Tantalus Fossae faults are a great example of a surface feature known as grabens; each trench formed as two parallel faults opened up, causing the rock between to drop down into the resulting void.