What fine silt from glacier grinding is also called glacial flour?

Fine silt produced when a glacier grinds bedrock is called rock flour, also known as glacial flour. As rock-laden ice moves over the ground, abrasion pulverizes the underlying rock into extremely small particles, commonly in the silt or clay-size range.

Meltwater carries this powder away from the glacier in suspension. The resulting water can look gray, white, or blue-green and is sometimes called glacial milk. When it enters a lake, the suspended particles can help create the striking turquoise color seen at places such as Lake Louise in Canada and Lake Pukaki in New Zealand.

Rock flour is not the same as loess. Loess is a wind-deposited sediment that may contain glacially produced particles after they have dried and been blown away. Scree, by contrast, consists of angular rock fragments accumulated at the base of cliffs, while peat is an organic soil formed from partly decomposed vegetation.