Gradiometry

Fluxgate gradiometry is a non-intrusive scientific prospecting technique that is used to determine the presence/absence of some classes of sub-surface archaeological remains (e.g. pits, ditches, kilns, and occasionally stone walls). By scanning the soil surface, geophysicists identify areas of varying magnetic susceptibility and can interpret such variation by presenting data, measured in units of nanoTesla (nT), in various graphical formats and identifying images that share morphological affinities with diagnostic archaeological remains.