Wednesday, October 10, 2007

Glacial Boulders

The top of the second ridge of hills that I hiked to all summer has numerous large glacial boulders that appear to have been broken when they dropped from a glacier around 10 000 years ago.

In the first photo you can see that the large boulder was cracked nearly in half. In the background, you can see three other boulders near the edge of the hill.

The second photo shows another one that has been cracked as well. The two pieces in the foreground look like they are part of the larger one in the background. This boulder is around 5.5 feet in diameter.

If you travel 10 000 years back in time, this area would be under a river of ice that was probably in the process of melting. I suspect the boulders on this hill fell from the ice to the ridge and cracked when it hit the solid bedrock, leaving all the pieces where they fell. If it had been cracked in the ice, the pieces would have been more rounded and separated because the ice in the glaciers flows like a river in slow motion carrying rocks and debris with it.




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