Sci Station Canada

Sunday, May 23, 2004

Canada rises above the USA

More Plate Techtonics a little closer to home this time ...

The United States is slowly sinking, and Canada is on the rise – all thanks to a glacier that melted over 12,000 years ago. Scientists have discovered that the melting of North American glacial sheets is still shifting the makeup of the land. For one thing, the shift is causing Canada's Great Lakes to slip slowly southward. Chicago, for example, is sinking at a rate of 1 millimetre a year. At current rates, Chicago's Sears Tower will be below water in approximately 462,686 years.

This is according to Seth Stein, a Northwestern University (Evanston, IL) geological science professor who helped organize the new study. According to Stein, "Over 20,000 years ago the glacial sheets created depressions and other natural features in the North American landscape, including the Great Lakes. When the ice began to melt – a process that began 12,000 years ago – the land slowly began to “rebound” and return to its original shape.

"Rebound"? OK, the earths crust is elastic, but surely it still needs a force? Perhaps upward thrust from the core or (more likely, IMO) the lightening of the load on the Canadian crust with the retreat of the ice & glacier coverage?

Professor Richard Peltier, a physics professor at University of Toronto and leading expert in field ... said he had been predicting the shifting elevation patterns for years and was happy they had finally been confirmed.


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