Just realized how a single rock in a creek bed taught me about glacial polish

I was hiking near Lake Tahoe last fall and met this older guy who was just staring at a flat, smooth boulder in the stream. He told me to run my hand over it and said, 'Feel that? That slickness isn't from the water. This whole valley was under a mile of ice, and that rock got sanded down like a piece of furniture.' I'd never really thought about glaciers leaving a literal polish on stone. Has anyone else found a spot that clearly shows that kind of ancient ice work?

3 comments

3 Comments

hart.sage5d ago

My buddy Mike saw it in Yosemite. He was on a trail crew near Tenaya Lake. They had to move a huge slab for a path. The underside was still rough and jagged. But the top was glassy smooth, like it had been buffed for a thousand years. He said it hit him that the ice did that, not people.

leo_fisher5d ago

Ever notice how old sidewalks get that same worn-down dip in the middle? There's a spot like that by my old apartment, smooth as a river stone from all the feet. Makes you think about all the people who walked there.

taylorc405d ago

That "glassy smooth" top is such a wild image. It really hits different than a worn sidewalk, like what leo_fisher mentioned. One is from a million people, the other is from a million years of ice just slowly doing its thing. Makes you feel tiny in the best way.