Site 380 - Geophysics Earth Resistance Survey Report - Heritage Non-intrusive Survey Reports Group 025

The survey was undertaken using a Geoscan Research RM15-D earth resistance meter configured in a parallel twin-probe array system with multiplexer allowing for two pairs of two parallel electrodes (four total) spaced 0.5m apart. One current and one potential electrode (the remote or static probes) are fixed firmly in the ground a set distance away from the area being surveyed. The second current and potential electrodes (the mobile probes) are mounted on a frame and are moved from one survey point to the next. Each time the mobile probes are inserted into the ground an electrical circuit is formed between the current electrodes and the potential gradient between the mobile and remote probes is measured and stored in the memory of the instrument. The survey area was divided into grids measuring 30m by 30m, established using a Trimble R10 RTK GNSS instrument. The Trimble R10 system receives corrections from a network allowing for a precision of 0.01m in real-time therefore exceeding the level of accuracy recommended by EAC guidelines.The instruments logged each reading at 1m intervals on traverses 1m apart within each grid. The mobile probe spacing was 0.5m with the remote probes 20m apart and at least 20m away from the grid being surveyed. This probe spacing of 0.5m gives an approximate depth penetration of up to 1m for most archaeological features. The HS2 Ltd Phase 2a GWSI: HERDS document identifies that EEW Group 025 falls within two distinct Recognised Archaeological Zones (RAZ), specifically RAZ 31 and RAZ 32. Site 380 falls within RAZ 31, designated for the preservation of buried remains and extant earthworks associated with the deserted medieval village (DMV) known as Godwynesleigh. The survey has not identified any anomalies of clear archaeological potential however a spread of high resistance readings of uncertain origin approximately 150m south-east of a previously identified site of a possible DMV referred to as Godwynesleigh, may have an archaeological cause, however the limited scope of the survey area west of Gonsley Green Farm restricts are more confident interpretation of these anomalies. The only other finding of limited archaeological potential is a possible pattern of ridge and furrow cultivation identified c.100m south of Gonsley Green Farm. Outside of these findings the survey has recorded a number of other geophysical anomalies all of which likely have a modern agricultural or natural cause. Faint parallel linear trend anomalies identify modern ploughing regimes and a low resistance linear anomaly south of the farm likely identifies a field drain or buried service. Multiple patches of large amorphous high resistance readings, likely record localised variations in soil moisture content, soil formation or superficial geological deposits across the southern part of the Site.