GeologyRocksPolar Caps causing crustal unit shifting?
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Re: Polar Caps causing crustal unit shifting?
Wed, 08/02/2006 - 21:18I have heard this theory in a couple ways; firstly, it was on a TV show a long time ago. It showed a depiction of the earth with a large arctic polar cap. It explained that if the cap got too large, it would pull the crust (as a whole) around to the bottom. I immediate thought this was funny, because it implies that there is a separate gravitational force acting on the ice mass. An example would be putting a beachball into a pool and sticking a weight on top of it - it would keel over. Obviously not comparable to actual forces being described in the show.
The words "cobblers", "of", "old" and "load" come to mind, but not necessarily in that order.
Plates move via continental drift - adding a weight on top of them (mountain range, ice cap, big pile of sediment) just depresses them (not in the psychological sense 
) - isostacy. No lateral movement will (or can) occur as there is no sideways force.
J.
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Polar Caps causing crustal unit shifting?
Wed, 08/02/2006 - 23:29I agree whole-heartedly with you both. Nothing was cited, so I was very weary as to if it were actual researched material or just a bit of crap on the side
I know that some geologists (including an old Earth Systems Evolution prof of mine) have researched continental drift as a cause of 'sliding down' the mantle. Here's what I mean: The position of the Africa plate has changed very little for millions of years, and it's thought to be the central point as to where the break-up began. And when you look at the coast line, the entire continental shelf is exposed. The hypthesis behind this is like sitting something on a hot plate - it will rise due to the heat underneath it. The same idea has been applied with Africa. Hence, some of the other continents broke away and 'slid downhill' as an easy way to put it.. Whether this idea has been confirmed, I have no idea. But I've read some material on it from the past couple years.
But as far as sliding into the depression of glacier? Isostatic rebound happens in 10s to 100s of thousands of years... No where near long enough for continents to move that drastically, as the 'article' suggests.
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Polar Caps causing crustal unit shifting?
Thu, 08/03/2006 - 02:13Not only that, but did you get a look at his site? He has a link to a picture that he claims are islands in some bay that are not really there. The "islands" are clearly low-lying clouds. There are other things on his site that scream "I am a lunatic!" IMHO.
Thanks for the link, though! It was a little levity in my trying day.
Canadarocks
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Polar Caps causing crustal unit shifting?
Submitted by ou_geology_guy on Wed, 08/02/2006 - 17:31.I have heard this theory in a couple ways; firstly, it was on a TV show a long time ago. It showed a depiction of the earth with a large arctic polar cap. It explained that if the cap got too large, it would pull the crust (as a whole) around to the bottom. I immediate thought this was funny, because it implies that there is a separate gravitational force acting on the ice mass. An example would be putting a beachball into a pool and sticking a weight on top of it - it would keel over. Obviously not comparable to actual forces being described in the show.
Then I came across a website trying to describe it a little different. I found it difficult to follow the train of reasoning. Perhaps someone else might have some insight as to whether this has some scientific backing?
http://www.peter-thomson.co.uk/ice-ages/Ice_age_theories.html
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