Faith,
IF there was such a flood THEN the effects predicted in the opening post either would not have occurred or would not have had the devastating effects predicted.
And IF the flood didn't happen & mass extinctions were a corollary of the impacts, then we would see this in the fossil record. We do. If the flood happened, we wouldn't. A very simple evidentially informed choice seems to be in order. Of the two positions, one has data consistent with it & the other doesn't.
Combine that with a total lack of evidence for a global flood, & well, you get the picture.
Mark
There are 10 kinds of people in this world; those that understand binary, & those that don't