[Geology2] Re: Did a massive volcanic eruption in India kill off the dinosaurs?

The atmospheric effects of the volcanic eruptions were spread out over about 3/4 million years, and their toxic effects would presumably have built up and declined over time rather than in a sudden surge. On the other hand, the impact of an asteroid would have had highly lethal effects concentrated over a very short time span, possibly days, or up to a few months.  I doubt that we will ever be able to date the extinction event closely enough to decide which of these two mechanisms killed off the dinos on that basis.   But there is a suggestion in the fossil record that the types of animals that survived the extinction period were those that could find temporary refuge from short-term hostile environmental conditions; birds and burrowing animals such as some of the mammals survived, as did frogs and crocodiles. The whole biosphere was probably highly stressed by the effects of the volcanic eruptions at the time of the extinction

I would guess that paleontological evidence will eventually be more definitive on this. The one-two punch makes sense to me.

Clay

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Posted by: fossrme@yahoo.com

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