Magnetometry Survey at West Harrogate Growth

Prior to the commencement of the fieldwork, the survey control was predefined in AutoCAD using a topographical drawing provided by the client. Base lines were plotted within the digital mapping to ensure comprehensive data coverage by the operator. The grid points associated with these base lines were exported from AutoCAD and imported into a Trimble R10 Global Positioning System (GPS). This instrument was used to set-out the grid points in the field using bamboo canes as non-magnetic flags. Survey tapes were used for heading and positional markers. A SENSYS MX Compact V3 gradiometer was used to collect the data. This system is GPS enabled and comprises 8 sensors spaced 0.5m apart operating at a frequency of 40 Hz. The system is mounted on a survey cart that is pushed by the operator in straight traverses using the baselines for heading references. Several magnetic responses indicative of possible anthropogenic activity were recorded, the most significant, a potential enclosure. Elsewhere, numerous weak or fragmented linear responses and spreads of magnetically enhanced material were identified; though these lacked sufficient form or context to be confidently interpreted as archaeological and have been classified as undetermined magnetic enhancements. A range of additional magnetic anomalies were detected throughout the length of the easement. Many relate to agricultural activity, including extensive ridge and furrow cultivation, modern ploughing and drainage systems, as well as former field boundaries recorded on historical mapping. Other anomalies were attributable to natural geological or hydrological processes, particularly near Clark Beck, or to modern intrusions such as utilities, gates, and ferrous debris.