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RE: Scientists conclude asteroid, not volcanoes, wiped out dinosaurs

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Phillip Bigelow
> Considering the volume of lava produced, probably a 
> butt-load.  Butt, (err....but,) it was expelled over millions 
> of years, not instantaneously, so the noxious gasses had time 
> to dissipate between eruptions, which were very infrequent.  
> I doubt that animal life was significantly affected by the SO2.
SO2's primary impact from volcanoes is climatic rather than toxic.
Sufficiently powerful eruptions through it up into the stratosphere, where
it can aerosolize into H2SO4 droplets. These have a chilling effect:
absorbing incoming sunlight and outgoing infrared. Big single eruptions
(Tambora, Pinatubo) had impacts that lasted a few years long each. It might
be that multiple degassing events from these volcanoes might well have
produced major chilling episodes.

Of course, if there were sufficient C02 in the eruption, there would be a
warming rather than a chilling effect. That is why the details of any
eruptive system are important.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA