Antarctic drift

February 4, 2011

We are not talking about snow drift here, but tectonic plate drift. Antarctica wasn’t always at the South Pole, and it won’t always be.

Until about 170 million years ago, Antarctica was part of the Gondwana supercontinent and was located far from the polar regions. (Before that, back to about 500 million years ago, it had been part of Pangaea. In the Cambrian period it actually straddled the equator.)

The Gondwana supercontinent (Image: THS Earth/Space Science)

As Gondwana slowly broke up, Antarctica, still joined to Africa, Australia, and South America, drifted south. At this time it was home to numerous dinosaur species, and was forested. It separated from Africa about 160 million years ago, and then from Australia 40 million years ago. It was still far enough north to have a sub-tropical climate, and in this period Antarctica, like Australia, had marsupials.

Early Cenezoic Antarctic marsupial (speculative).

Roughly 23 million years ago its southward drift caused it to separate from South America. I am no geologist, but to me it seems that I can actually see this separation happening on the map: the Antarctic Peninsula reaches out toward Tierra del Fuego and gives every appearance of having been violently ripped away, the islands floating off like shards splintered from the torn seam. It would be interesting to know if there is any truth in this seeming.

Source: Wikipedia

For the last 15 million years, Antarctica has been covered in ice, and it has been a cold and silent place. Today the continent is drifting slowly, at the rate of a few centimeters (~an inch or two) per year, toward the Atlantic Ocean. It will not be a frozen world forever, and when its ice does melt, all those pretty beach houses along the world’s coasts — the ones, at least, that have been built to last — will get water damage.

3 Responses to “Antarctic drift”

  1. Adam Hincks Says:

    Congratulations on gaining your first (I presume) Marsupial tag. Isn’t it incredible that modern science can show us such accurate renditions of Antarctic Cenezoic fauna?

  2. Janet Says:

    For some reason that marsupial reminds me of Harvey. I know that Harvey was supposed to be a big rabbit, but maybe Elwood P. Dowd had never seen a kangaroo before and Harvey was too polite to correct him.


  3. cburrell Says:

    I’m no biologist, but is it possible that rabbits evolved from Antarctic marsupials?

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