The Gravity Anomaly Map UK South is a colour contour map that shows variation in the gravity field over the southern part of the UK landmass and adjacent sea area at a scale of 1: 625, 000. Contour values are shown as Bouguer anomaly onshore and free-air anomaly offshore. Gravity and magnetic anomalies show small departures from the expected values of the earth`s gravity and magnetic fields, caused by variations in the density and magnetisation of the rocks within the crust. These anomalies are used to determine concealed geological structure, including the depth and extent of sedimentary basins, depth to magnetic basement and location of concealed igneous bodies. On the broadest scale, they help to convey an understanding of the regional configuration of the Earth`s crust and upper mantle.