Always Physicist and Geologist that push this ridiculous hypothesis, Never Paleontologist.
a giant asteroid that hit the coast of Mexico 65 million years ago probably incinerated all the large dinosaurs that were alive at the time in only a few hours,
Bull, For one some Dinosaurs made it into the Tertiary (Examples here and here)
and only those organisms already sheltered in burrows or in water were left alive.
Birds & ungulate mammals were able to burrow???
"The kinetic energy of the ejected matter would have dissipated as heat in the upper atmosphere during re-entry, enough heat to make the normally blue sky turn red-hot for hours," said Robertson. Scientists have speculated for more than a decade that the entire surface of the Earth below would have been baked by the equivalent of a global oven set on broil.
So not only were the birds & ungulate mammals able to burrow, They were able to stay underground for more than 10 years???
Plus even if Alligators and Frogs were underwater during the impact wouldn't they die when they came up to breath? Plus the heat would have quickly evaporated the lakes and ponds they lived in.
The evidence of terrestrial ruin is compelling, said Robertson, noting that tiny spheres of melted rock are found in the Cretaceous-Tertiary, or KT, boundary around the globe.
Whoppee!! Those spheres are found everywhere not just in the KT boundary.
Here is an example of 2 layers above and below the K-T boundary
A nearly worldwide clay layer laced with soot and extra-terrestrial iridium also records the impact and global firestorm that followed the impact.
Wrong. The nature of the soot doesn't show it was massive amounts of vegetation that burned at the time, In fact it shows the opposite. The soot contains very little charcoal which if a lot of vegetation was burned you would expect a lot of it and Abundant vitrinite (coalified plant tissue) is recorded. Plants can't turn to coal if they are burned!!!
As for the "Extra-terrestrial" iridium layer, iridium can come from volcanoes and the layer at the K-T also contains high arsenic, antimony and selenium levels which are common earthly elements but rare in meteroites. Plus Iridium is missing from the Chicxulub crater itself!!!!! How can an Asteroid or whatever (It's still not proven to be a meteror crater and it's looking like one less and less) that caused the Chicxulub crater produce a iridium spike around the world when it didn't contain iridium?
The spheres, the heat pulse and the soot all have been known for some time, but their implications for survival of organisms on land have not been explained well,
Sure it has, I T D I D N 'T H A P P E N.
Their answer closely matches the observed patterns of survival. Pterosaurs and non-avian dinosaurs had no obvious adaptations for burrowing or swimming and became extinct.
Neither did birds, Yet they lived.
In contrast, the vertebrates that could burrow in holes or shelter in water -- mammals, birds, crocodilians, snakes, lizards, turtles and amphibians -- for the most part survived.
And what about all the Dinosaurs like Mesosaurs they were able to swim? How come they went extinct?
Terrestrial vertebrates that survived also were exposed to the secondary effects of a radically altered, inhospitable environment. "Future studies of early Paleocene events on land may be illuminated by this new view of the KT catastrophe," said Robertson.
There already has been studies, That's why most Paleontologist don't believe this dumb hypothesis anymore.