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Re: SPECULATION: pterosaur extinction versus bird survival



At 5:24 PM -0500 2/5/01, Ray Stanford wrote:
Hello list,

    Hopefully I may be forgiven for discussing pterosaurs on a dinosaur
list, but some speculation concerning possible contributing factors to
pterosaur extinction coincident to the K/T boundary event(s) comes to mind.
"Event(s)" is used here in reference not only to the impact event, per se,
but to various environmental changes initiated by it over an undetermined
period of time.

    Please consider what follows as speculation or questions about what
might, conceivably, have happened, rather that as established fact:

    It seems likely that the initial impact event would have caused very
severe winds not only within a few thousand kilometers radius to the impact,
but even world-wide, within a very short time compared to the development
time of more normal weather/wind systems.   At a somewhat lessened level,
very severe weather/wind systems would probably have continued, world-wide,
for weeks or maybe even months.

Sorry..... but recent discussions I have been having with several astrophysicists lead me to currently say, despite popular depictions, that there are good chances are that "it" probably didn't "impact" at all. I recognize that this could be perceived as out of the box thinking, but then, I'm not in sarcophagus yet. "It" probably vaporized some distance above the earth, large chunks of it falling out spectacularly, etc. (e.g., Tunguska) Among other things the downward force of the winds of the explosion would have blasted trees flat, the ensuing immediate fires would have been snuffed out almost as instantly as the available oxygen was sucked upward in the mushroom cloud, and the particles left over would have begun circulating in the troposphere and distributing itself upwards, not to mention the very kewl seismic waves that would have accompanied such a blast, probably and last, but not least, anything unfortunate to be within the immediate regions was barbecued beyond all believable bounds - I love catastrophic death - leaves more in the rock for me...... ;^)


Severe global climate change due to so many particles in the atmosphere would have lasted for years, not just a few months. There is "lag time" in global climate. For instance - even if ENSO-like events did occur in the Cretaceous paleo-Pacific, what would have been the effect on them by an impact scenario, and would those effects have propagated well northward in the area influenced by the Cretaceous Interior Sea? Just one aspect to consider......

Just thinking out loud.

Cheers,
Marilyn