Pit chains are numerous in the Alba Patera region, occurring mainly tangential to Alba Patera in a NE orientation on the eastern side and a NW orientation on the western side.
Pit chains are collapse structures, lacking an elevated crater rim, ejecta deposits or lava flows that are typically associated with impact craters or calderas. The individual pits typically have a conical shape with or without a flat floor, stratification and differential erosion;
we hypothesize that pit chains may largely originate by dilational normal faulting and fissuring.
Pit chains are generally observed in regions that have experienced crustal
extension, such as the numerous grabens in the Alba Patera and Valles Marineris region.