Protonilus Mensae

The mesas and valleys in this VIS image are part of Protonilus Mensae. Located between the relative highlands of northern Terra Sabaea and the lowlands of Vastitas Borealis, Protonilus Mensae is region of chaos terrain. Chaos terrain is typified by regions of blocky, often steep sided, mesas interspersed with deep valleys. With time and erosion the valleys widen and the mesas become smaller. It has been proposed that a catastrophic outflow of subsurface water creates the chaos. Protonilus Mensae also shows signs of glacial flows, which would continue to modify the surface.