October 04, 2006
This is a nice example of reflection symmetry photographed from about halfway round the walking trail of Emerald Lake, in Banff National Park, Alberta, Canada. Photo taken in late May of 2006. Obviously there was hardly a breath of wind for the distant mountains to be reflected so clearly in the surface of the lake. The name of this lake is of course due to its characteristic emerald color, caused by so-called rock flour, which consists of clay-sized particles of rock, generated here by glacial erosion. Because the material is very small, it's easily suspended in river water, making the water appear cloudy. When river water flows into a glacial lake, as here, it can appear turquoise in color. Rock flour is also produced by freeze thaw, where the act of water freezing and expanding in cracks helps break up rock formations. See also the Earth Science Picture of the Day for August 28, 2002.