The process of collecting and analysing unconsolidated soil sediments in order to locate geochemical anomalies in the underlying rock and to use these to find orebodies. Where the loose material or soil is stable there is a geochemical balance between the original rock, weathering, pore water, and biological activity. The soil profile is usually layered, and in a geochemical soil survey the horizon giving the sharpest contrast between background and anomaly is chosen for analysis.