QUESTION:
When Antarctica was a part of Pangaea, were volcanoes ever active or did
it ever have a tropical rain forest? In other words, how long ago did it
have the environment that it has today, and what was the environment
like prior to that time?

        From Christopher D., Crockett Jr. High, Seventh grade, 
             Irving, Texas

ANSWER from Scott Borg, Program Director, Office of Polar Programs
            Antarctic Geology & Geophysics Program        
            National Science Foundation
            Thu, 20 Feb 1997 10:50:04 -0500

Dear Christopher,
       
The current Antarctic ice sheet started to grow about 35-40 million years
ago. By about 18 million years ago the ice sheet was pretty much as it is
now.  Some scientists think that it may have diminished to a much smaller
ice sheet for a short period of time about 3.5 million years ago (mya).
Prior to the development of the ice sheet (about 35 mya), the climate was
most likely kind of like southern South America.  Unfortunately, there are
very few sites in Antarctica with geological records of the environment for
the early Cenozoic (65-35 mya) so environments for that period of time have
to be inferred from other information.

For the late Paleozoic and Mesozoic, there are many unequivocal lines of
evidence documenting the existence of forests and lakes and animals and
such, even large carnivorous dinosaurs during the Jurassic (about 200-180 mya).
I think that there is evidence of temperate rain forests but not tropical
rainforests, unless perhaps you go back in time to the Permian (about 260
mya).  Coal deposits indicate prolific vegetation during the Permian but I
am not sure that this means that tropical rainforests existed.  In the
Permian, there is also evidence of a widespread glacial episode so I don't
think that a truely tropical climate was likely.

Thanks for your excellent question!
Scott Borg