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Re: Warm- vs. Cold-blooded Dinos

>From: Ellin Beltz <uebeltz@uxa.ecn.bgu.edu>
 > In the endo/ecto debate, does the increased temperature of the Mesozoic 
 > play a part?  Climatological data indicate that this was the warmest 
 > period of earth history. 

Well, the warmest since the Precambrian, anyway.

 > It also had the highest carbon dioxide 
 > atmospheric levels.  (See June 1995 Geology for discussion of source of 
 > Mesozoic atmospheric CO2). 
 > It has been suggeted that there was little temperature stratification 
 > between the equator and the poles during this time. 

Little, but *not* none.  The leaves of flowering trees make an
excellent climatic indicator.  Based on this criterion, the climate
of the Alaskan north slope during the Late Cretaceous showed an
average annual temperature of about 5 degrees Centigrade.  Given
that there would have been an extended period of dark in the winter,
this implies that temperatures probably dropped below freezing almost
every year, at least for a few days.

Now in fact, this was *far* warmer than that region is now. In fact I
do not think anyplace in Canada, except perhaps British Columbia, has
a climate like that.  [The average temperature beyond the Arctic
Circle today is below zero Centigrade].

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.