Bouguer anomaly

Anomaly in the local gravitational force that is due to the density of rocks rather than local topography, elevation, or latitude. A positive anomaly, for instance, is generally indicative of denser and therefore more massive rocks at or below the surface. A negative anomaly indicates less massive materials. Calculations of Bouguer anomalies are used for mineral prospecting and for understanding the structure beneath the Earth's surface. The Bouguer anomaly is named after its discoverer, the French mathematician Pierre Bouguer, who first observed it in 1735.