Sunday, July 06, 2008

When the ordinary is extraordinary in VT: glacial erratics

A couple of days before I left for Vermont I was having an e-mail correspondence with a friend of mine from Australia. For no particular reason, I sent him five photos of my property in Vermont and the surrounding area. One of these photos is the photograph of the Lake in front of my cabin taken at sunset showing a large granite boulder sitting in about eight feet of water.

This is a favorite photo of mine (see the top photo), and I have about five different digital photos and who knows how many photos that predate digital photos. I have showed some version of this photo to many people over the years.

When my friend wrote back to me thanking me for the photos, he inquired:

“I find myself wondering how the rock got there?”

This very simple question got me thinking. I wrote back telling him the very short story of the geological history of this part of Vermont, that when glaciers passed over this area several thousand years ago large boulders were dropped at random and haphazardly. When the ice sheet retreated, these boulders, sometimes called glacial erratics were often left standing alone in a field, in a forest, or even in a body of water. In case you are wondering, according to local geologists, many of these erratics are granite.

Because it was only a few hours before my imminent departure, I had time for only the briefest of explanations to my friend, who also marveled at the trees. I wrote him a shorter version of the preceding paragraph and sent him some Internet links explaining local geology and forestry.

I was very glad for my friends question about how the rock got in the lake for it made me think about how unusual this rock is. I have taken this rock for granted for more years than I care to admit here. I never wondered how the rock got there because I always knew how the rock got there. I tried to put myself in the shoes of someone who had never been to this part of America before. I don’t take the erratics that are all too common in this part of New England for granted any more. I wanted to find one photograph that showed an erratic boulder in all its glory to show my friend (bottom photo). And I remembered this erratic on the high spot of a shoulder of a mountain. This photo is for my friend in Australia.

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