Developments in geophysical survey techniques
In January and February 2018, AS carried out a cart-based magnetic gradiometer survey at a site in Norfolk.
We have had the capacity for GPS tracked cart-based survey for some time but this was the first time that the team had attempted to use the equipment for highly accurate 0.5m sensor traverses. The survey was challenging and new data processing regimes had to be created to remove the heading errors inherent in gradiometer survey.
The results obtained were of high quality and resolution, allowing the more precise identification of probable sub-surface features. A number of ditches are visible in the processed data, including a possible sub-rectangular enclosure in the south. In addition, were numerous large pit-type features, mainly concentrated in the centre of the survey area. The sub-rectangular form of some of these may indicate the presence of Anglo-Saxon sunken-featured buildings (SFBs), which appear to be accompanied by possible thermoremanent features (hearths/kilns). Patterning in the data are caused by periglacial activity and the remaining striping is from the direction of modern ploughing.
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