Final answer:
Glacial drift best describes the sedimentary materials outwash and till deposited by glaciers. These materials provide insights into past glacial movements and influence soil formation, topography, and geochemical signatures of landscapes.
Step-by-step explanation:
The term glacial drift refers to the sedimentary materials outwash and till, which are deposited by glacial action. As ice sheets move across the land, they weather and erode the surface, carrying with them a variety of sediments ranging from fine silt to large boulders. This material, when deposited, is known as glacial drift. It varies in composition and is often used to trace the past movements of glaciers, as it leaves a geochemical fingerprint that can be matched to rocks on continents, helping to determine the historical extent of ice coverage.
An understanding of glacial drift is essential in fields such as geology and geography because it influences soil formation, topography, and the geochemical landscape. For example, glaciers can completely transform areas by eliminating pre-existing soils and introducing new materials on which new soils can develop. Furthermore, as glaciers retreat, they can leave behind diatom-rich layers indicating periods of ice sheet retreat, or diatom-poor layers that reflect ice sheet advance toward the coastline.