Magnetometry Survey, Geophysical Survey at Land at A134, Great Cornard, Sudbury, Suffolk

A temporary grid system was established over the site and marked out using canes. The location of the grid was set out using an RTK GPS system theoretically accurate to some 0.01m and referenced to OS co-ordinates. Data was collected using a cart carrying four paired Bartington magnetic sensors. Four sensors mounted 1m horizontally apart and very accurately aligned to nullify the effects of the earth's magnetic field. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. Each data point is geographically referenced using an on-board Trimble RTK survey grade GPS system. Readings were taken at 0.125m centres along traverses 1.0m apart. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. The magnetometer survey has recorded magnetic responses that have been interpreted as being of possible archaeological interest. In Area 9 magnetically weak ditch-like response appear to form a series of rectangular enclosures and a ring ditch. Three magnetically strong responses in Areas 5 and 6 could be former kilns or be due to ferrous material / objects. Numerous uncertain anomalies have also been detected in the survey; these include linear responses and pit-like anomalies which could be due to a combination of natural and agricultural processes. A number of former field boundaries and a land drain have also been mapped. Weak amorphous response visible throughout the data have been caused by variations in the underlying geology. The routes of service pipes have also been marked in the survey.