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Re: Age Abstractions
At 21:07 2007-06-20, evelyn sobielski wrote:
And what is suspect about this one is the locality.
There probably was little more inhospitable terrain in
the earliest Paleogene than the
southwestern/south-central US... if the present
estimates about impact angle of the Chixculub bolide
are correct, it received far more of the immediate
consequences (and ejecta) and relatively more of the
mid-term consequences than most other places on Earth.
The area in question must have been literally
If he'd had dug up his find on Chatham Island, *that*
would be interesting indeed. But this is simply
I don't agree with that. True, being within a couple of thousand
kilometers from Chicxulub would certainly have been lethal (ejecta
blanket, IR flash, superheated steam shockwave etc), but the zone
beyond that may actually have been the least bad place on Earth to
be. The reason for this is that only relatively low energy ejecta can
re-enter close to the original impact. Being near the antipode of
Yucatan (e g Madagascar or India) would be much worse. The IR
radiation from re-entering ejecta there would be lethal to almost
anything not underground or underwater. However the early Paleocene
of the western US is uniquely well known, so it seems highly unlikely
that any surviving dinosaurs there wouldn't have been found long age.
Chatham Islands however also seems unlikely as a refugium. Recent
work in New Zealand suggests that the effects of Chicxulub were very
bad there too. I would suggest Antarctica as the most likely place.
It does seem that a lot of the extant dinosaurs originated/survived there.