Geophysics

Caesium Gradiometry


The caesium gradiometer
 measures the varying magnetic susceptibility of soil. It is a more sensitive instrument than a fluxgate gradiometer traditionally used by archaeologists, and therefore offers the opportunity of seeing below the ground, both in more detail and to a greater depth.

As this equipment is more sensitive, it is useful when archaeological features are difficult to distinguish from the surrounding soil. It is particularly useful on igneous geologies and in areas characterised by gravels.

The plateau at Yeavering is composed of natural gravel, so this type of survey was trialed to see if features, both known and unknown, could be detected and characterised. 

Although the technique proved useful in locating the foundation trenches of the known Anglo-Saxon buildings, its precision in showing the underlying geological variation and natural anomalies made any detailed information on the site difficult to interpret.