This complicated area contains various types of channels, pits and fractures. We can determine the relative ages of the pits and channels based on which features cross-cut others. Older channels appear smooth-edged and shallow. Younger channels and pits are deeper and more sharp-edged, as well as less sinuous than the shallower channels.
What caused this array of various channels and intersecting pits?
This region is covered in vast lava flows. The collapse pits here may be collapsed lava tubes or where overlying rock “drained” into voids created by extensional faulting. [More at link]