"What I believe to be the case is that once you admit the possibility of even one cosmic catastrophe such as the flood at the time of Noah, then basically all of the assumptions which dating schemes are based on go out the window."
Why ? A flood could have occured with any effect whatsoever on the fossils that were laid down millions of years before. Would a flood somehow change radioactive decay rates ?
So this Bob Bass took Lord Kelvin's numbers, which were supposed to be some sort of proof, and revised them.
Who is to say that Bob Bass neglected to consider something in his computations that would extend it by a few more decimal places ?
The author of this article uses a lot of your same arguements - do you agree with him that dinosaurs and therefor their fossils, are all younger then a few tens of thousands of years old ?
http://designeduniverse.com/th/agesofearth/
No, but whatever caused the flood could easily have changed the ratios or regular to radio carbon on the planet. Radiocarbon dating depends on those ratios having always been as they are now.
Likewise having heavy metals near the surface of the Earth due to impact events would mean that dates derived from those metals would be good for the metals and that was all.