Soil which fill the voids among sand grains. Silt is mineralogically like sand but with its higher specific surface area it is more chemically and physically active than sand. But it is the clay content of soil, with its very high specific surface area and generally large number of negative charges, that gives a soil its high retention capacity for water and nutrients. Clay soils also resist wind and water erosion better than silty and sandy soils, as the particles bond tightly to each other, and that with a strong mitigation effect of organic matter. Sand is the most stable of
Geology of Great Britain is a varied distribution of unconsolidated material of more recent origin. It includes material deposited by glaciers (boulder clay, and other forms of glacial drift such as sand and gravel). "Drift" geology is often more important than "solid" geology when considering building works, drainage, siting water boreholes, sand and gravel resources and soil fertility. Although "drift" strictly refers to glacial and fluvio-glacial deposits, the term on geological maps has traditionally included other material including alluvium, river terraces, etc. Recent maps use the terms "bedrock" and "superficial" in place of "solid" and "drift". This description of the geological history of Great