The meteor theory is that of a worldwide disaster. Traces and aftereffects of this meteor collision are well recorded in those layers relating to the demise of the dinosaurs. Its not that scientists make this stuff up, they debate the for and against arguments for decades, and the general conclusion is that there are extensive signs of a meteor collision at the demise of the dinosaurs, and yet no such signs at the demise of the Permian. You would have this initial impact (whiplash) folowed by tsuanmis, and then darkness , bringing on an ice age. these are all logical scientific projections of a large meteor impact. The coldness and reduced sun would cause a lack of vitamins in dinosaur vertebrae, reducing their calcium production. Reptiles are completely reliant on sunlight for calcium production. Thus they had vertebrae problems at the moment of impact, and then continuously afterwards. this would have been difficult for any large dinos to survive. Maybe a few did.
I'm assuming this occurred at the end of those old great civilizations, that I also believe co-incided with the end of the holocene Climate Optimum. This was the great ice age that ended the dominance of dinosaurs and brought in the dominance of mammals to fill in all the ecological gaps left behind by the dinosaurs. Not saying mammals evolved much, just filled the gaps. I believe this occurred about 3500-3800 years ago.
Awesome, I am glad it is well supported. That sounds very plausible, and was interesting to read. Thanks for sharing.