I agree that this crater may be due to infill. However, as I said in response to Alex we should expect there to be volcanic cones in this region if this is indeed a region of hydrovolcanic activity.

In regards to Occam's razor, people have the tendency to forget that Occam's razor does not PROVE a hypothesis is correct. It only gives us a method of selecting among competing hypotheses BASED ON THE INFORMATION THEN AVAILABLE. It quite frequently turns out that with succeeding information the simplest explanation no longer becomes tenable and more complicated explanations become necessary, sometimes including those that were previously rejected.

Bob Clark