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Re: Ain't No Mountain Low Enough [elephants don't like steep terrain]



At 00:17 2006-07-28, David Marjanovic wrote:
I'm not sure that there
are any bonafide high-altitude fossil sites older than the Pliocene, though
there might be some in the Rockies (Florissant?).

Was it you who once mentioned the Gamburtsev Mountains in Antarctica onlist? Whoever did, however, ended by saying "Unfortunately, they're covered by about a mile of ice."

Indeed it was, and that is also a way that an old mountain chain might be preserved beyond the normal span. Normally we consider ice to be a powerful erosive agent, and usually it is. However in the central parts of an ice-cap the ice is often "cold-based", i e frozen to the substrate, in which case all motion takes place within the ice and erosion is virtually zero. This can be seen e. g. in parts of northern Sweden where the ice was cold-based during the last glaciation and the Eemian/Early Weichselian (MIS 5a-e) landscape is preserved intact under a very thin veneer of moraine.
The Gamburtsev mountains probably *are* quite old. At least there was a highland in that general area back before Australia and Antarctica separated. There are still traces of river valleys in Western Australia whose headwaters are truncated by the south coast.


Tommy Tyrberg