Hum,
while it is possible the more likely scenario (IMHO) is that the crater is a very ancient impact crater that has been eroded down and excavated leaving no trace of the ejecta, or original crater walls.
The `sedimentary` layers on the surface that overly the broken `gabbros` or breccias indicate the whole region was covered with water (or experienced the same process) that created the deeper layered formations seen in the crater wall formations.
The source of the breccias however maybe of volcanic in origin (or the eroded impact ejeca).

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`Irony` actually does mean `metal like`...