Site 053 - Geophysics Survey Report Heritage Non-intrusive Survey Reports Group 016

The survey was undertaken using four Bartington Grad601 sensors mounted at 1m intervals (1m traverse interval) onto a rigid carrying frame. The system was programmed to take readings at a frequency of 10Hz (allowing for a 10-15cm sample interval) on roaming traverses (swaths) 4m apart. These readings were stored on an external weatherproof laptop and later downloaded for processing and interpretation. The system was linked to a Trimble R8s Real Time Kinetic (RTK) differential Global Positioning System (dGPS) outputting in NMEA mode to ensure a high positional accuracy for each data point, in accordance with EAC guidelines (EAC 2016). The survey has identified anomalies indicative of cultivation techniques in both parcels of land. In the south of the eastern parcel, anomalies identified as field drains are recorded, whereas in the western parcel, linear anomalies indicative of more modern ploughing techniques as well as slightly curvilinear anomalies consistent with older, post medieval 'ridge and furrow' are recorded. High magnitude responses near or adjacent to existing field boundaries are caused by the presence of highly magnetic material either within the boundaries or as a spread of sub-surface material. Occasional, discrete, low magnitude and dipolar 'spike' anomalies are of natural and modern causes respectively.