Phase 2a Heritage Non-intrusive Surveys Report: Group 007 Site 270 Geophysics survey report

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 not identified any anomalies of definite or possible archaeological origin. Widespread covering of magnetic disturbance across all of Site 270 is characteristic of the recent spreading of organic 'green waste' as soil conditioner. The spread of magnetic 'noise' in this field however is not deemed to preclude the identification of magnetically weaker anomalies of possible archaeological origin. No anomalies were recorded that could relate to ridge and furrow identified in the ES (HS2 2017b) or three artefacts recovered from nearby Finners Hill recorded in Heritage Asset data supplied from the British Museum Portable Antiquities Scheme (PAS). The findings from the survey are consistent with the known limited archaeological potential of the area covered by LS-WSI Group 007.