We have seen the many science specials that show the dinosaurs looking up to see the flash of the huge asteroid impact that would doom them. There seemed to be good correlation between the impact and the extinction (called the K-T boundary) about 65,000,000 years ago. But a 0.05% error in dating either would cast doubt on the correlation, since the impact suggests a rather rapid extinction would take place.
The popular theory that Mexico’s Chicxulub Crater, discovered in 1978, holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, has been confronted by a serious challenge from evidence found in Mexico to suggest that the Chicxulub impact predates the K-T boundary by as much as 300,000 years. So this theory must be placed in a less certain category. Shucks, I really liked that theory.
The scientists suggest that the massive volcanic eruptions at the Deccan Traps in India may be responsible for the extinction, releasing huge amounts of dust and gases that could have blocked out sunlight and brought about a significant greenhouse effect.
Good old global warming, it can always be a possibility, from destroying the Cascade pika environment (news in the Seattle paper paper today) to mass extinctions. This is probably because the theory behind greenhouse gas warming is very strong.