How long did Antarctica exist?

Answer 1

Antarctica used to be part of the super-continent Gondwana. Less than 200 million years ago (Mya), it split off from Australia. In the Cambrian era, some of Antarctica used to be in the northern hemisphere, and with a mild climate, had ferns, trees, and lots of coal forming swamps.

In short, the Antarctic Craton has existed for at least the last 600 Mya. The Pangaea super-continent split into Laurasia and Gondwanaland, but there were probably several earlier super-continent assemblies that broke up and re-assembled.

Naturally, from this historic record, tectonic processes have destroyed or mixed up much of the early records, but science is working away on this intriguing problem.