Glacial Landscapes

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Observations - Erratics

We are standing on Pothole dome in Tuolumne meadows. The first microscopic feature we are looking at is called a glacial erratic. These gigantic boulders are sitting on a bare surface of rock. However, there is no apparent source, or mountain that they could have fallen down from!

glacial erratic

Observations - Polish

The next feature we see is glacial polish. The bedrock has been scoured as smooth as a kitchen countertop! Even more amazing is that you can actually see long scratches in the smooth surface, that all run in the same direction. In the pictures here, the shiny surface of the rock is not water (though it was cloudy the day the picture was taken, it did not rain). The rock on Pothole dome has been scoured so smooth by the glacier that it is shiny!

glacial polish glacial erratic