[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Antarctica moved too (was RE: Warm southern winters)



Tracy Ford wrote:

> It is possible that the unique conditions of polar WARMTH (my
> stress on this) coupled with a strongly seasonal light regime favours 
> these plants...
>
> Hmmm...a warm winter...hmm...


I'm not at all surprised that most of Antarctica experienced warm weather
back in the Crecaeous.  Just as Australia was in a different position back
in the Cretaceous, so was Antarctica.  The continent of Antarctica had yet
to occupy its current position straddling the South Pole.  According to one
interpretation, back in the Early Cretaceous only about a third to a half of
Antarctica resided within the current bounds of the Antarctic Circle (~66
degrees lat. S).  

After the two continents detached from each other, Australia migrated
northwards and Antarctica headed southwards.  One got warmer, the other got
colder.  (Okay, it's a bit more complicated than that, but that's the
general idea.)  But during the Cretaceous, Antarctica would be expected to
have climatic conditions not too different from most of Australia.  For both
continents, only a portion lay within the present-day Antarctic Circle.
This corresponds to the southeastern corner of Australia, and the adjacent
portion of Antarctica.  



Tim


------------------------------------------------------------------- 



Timothy J. Williams, Ph.D. 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 9359