I understand that there are currently three hypotheses as to how the Gambutsev Mountains were formed. Can you run us through them?posted by LobsterMitten at 8:52 PM on October 14, 2008 [2 favorites]
The fact that there are mountains at all in the middle of the East Antarctic landmass constitutes something of a mystery. It's really like finding a mountain range in the middle of a beach. There really shouldn't be mountains there.
* The first hypothesis is that Antarctica is in fact made up of two landmasses that collided 540 million years ago, forming the Gamburtsev in the process, and that the mountains have remained remarkably preserved because somehow their rock composition has impeded erosion.
* The second idea is that the same two pieces of Antarctica collided more recently than we thought, meaning that Antarctica isn't a stale, old continent as was previously supposed.
* And the third idea is that there may be a volcanic plume (or hot-spot) beneath East Antarctica - in essence a giant volcano beneath the ice sheet which is what has formed the Gamburtsev Mountains.
If the Gamburtsev where the result of a collision between two tectonic plates, how would that fit into the accepted theory that Antarctica was part of the Gondwana super-continent before its break-up?
It would suggest that during the break-up of Gondwana, as India and Australia wiggled away towards their present locations, Antarctica didn't stay as one piece - instead of being one big cookie, it was two cookies - and that the two pieces eventually moved back together, forming the Gamburtsev Mountains as they crashed back into each other.
Which theory do you favour at this stage?
I had thought the collision theory was the right one, but it is very hard to reconcile all the facts. For example, we haven't found any young sediments off-shore as there should be if the theory is correct. So perhaps it is a very young volcano and at this stage I think I'd lean toward the possibility of there being a hot-spot.
But according to recent measurements, if it actually is a hot-spot, it isn't actually very warm?
This would point to the volcano being very young. The whole edifice would have had to grow very recently, and not have had a chance to be eroded.
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posted by Caduceus at 4:03 PM on October 14, 2008 [29 favorites]