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Re: Pennsylvanian Extinction Query



Steve,
As for any local big extinction events in Illinois at the end of the Carboniferous, I would guess it most likely was caused by deltaic flooding, with silt smothering the brachiopods (and other groups) in the offshore area. I suppose this could have be intense during this particular time due to a combination of glaciations and volcanic activity causing rapid melting.
As for worldwide extinctions of various taxa, it wasn't much compared to the mass extinctions that would follow later. But if there was a fairly rapid decrease in oxygen levels, some of the larger brachiopods could have been hit hard by that.
In any case, I suspect that any mini-extinction at that time would have been caused by mainly geological and environmental stresses, not by any kind of major impact event. Well past my bedtime, but if I think of anything pertinent tomorrow, I'll post more information.
------Ken
******************************************* 
From: "Steve  Brusatte" <dinoland@lycos.com>
Reply-To: dinoland@lycos.com
To: dinosaur@usc.edu
Subject: Pennsylvanian Extinction Query
Date: Sat, 08 Sep 2001 21:02:53 -0500

Hey,
I apologize for a question that may appear to be off topic, but I do have a quick query regarding the Pennsylvanian (the period that holds my real interest...the Mesozoic is only my hobby!).

I'm currenly involved in a pretty exhaustive research project regarding Upper Pennsylvanian fossil faunas of Illinois. It seems as if at a certain point in the rocks, a mass death assemblage of brachiopods is found. Of course, this could be an artifact of preservation. And, since I have no real scenario yet to explain it, I may be dead wrong. However, this has gotten me thinking about a possible mini-mass extinction.

Unfortunately, the best available data on mass extinctions (Raup and Sepkoski's work) only covers the past 250 million years. I am working on a particular site that is somewhere from 290-300 million years old. Although Raup and Sepkoski never mention the Pennsylvanian per se (in the papers I have read), if their 26 million year cycle data is correct, than an extinction of some sort would be predicted between 290-300 mya!

So far, I have yet to find much information on a possible extinction. I've tracked down as many papers on the subject that I can find (which is very limited because I don't have access to a scientific library as of yet). However, I can't really find any clear cut data that suggests a bona fide mass extinction during this time.

My off topic question is this: is there any real evidence for a mini-mass extinction about 290-300 million years ago, where is evidence of it preserved, and what exactly did it cause in relation to fossils and paleobiology?

Any insights, both on list or off list, are appreciated!

Thanks,
Steve

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***************************************************************
Steve Brusatte-DINO LAND PALEONTOLOGY
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