glacial drift

The random spoils of a glacial incursion over land, whereby detritus is picked up in one place and set down in another, is called glacial drift. Occupying the time stratum between the drifting of snow and the drifting of continents, glacial drift represents the products of abrasion between resident earth and moving glacier. A drift map thus shows the deposition pattern of superficial material, which is left by glacial movement to overlie the bedrock features of a geologic formation. Drift materials may consist of erratic stones, landforms such as massed terminal and lateral moraines, drumlins dozed up by moving ice, or broad sheet deposits such as till or outwash, which are shaped by ice and left when glaciers retreat.

Kim Stafford