RE: "...conclusion cannot be logically supported..."
It really doesn't matter what the source of the CO2 was. In this case, since the climate change took place after the extinction of the dinosaurs, it's a 100% certainty that flatulence from sauropods had nothing to do with the warm up, either.
I'm sure that that's a huge comfort to the departed dinosaurs, as they continue to graze, ruminate and poot Big Ones, in the Elysian Aalanian Fields.
It does when you're using the argument to justify reducing CO2 output of human activity.