Geophysics dreamland

Secret weapon
With the massive landscape of an Iron-Age hillfort and associated settlements to survey, you might imagine that the geophysics team would have had its work cut out. The truth is that Wittenham provided the team with some ideal conditions and a chance to use its secret weapon.

'These have been fantastic conditions for us,' said Geophysics boss John Gater. 'The underlying geology, which is chalk around here with a bit of gravel at the top of the clump, is just perfect for magnetometry. We've covered some large areas and have obtained some really good results. The definition is very clear with wall foundations, ditches and pits all showing up really clearly.'

Special system
Geophysicist Ben Urmston used the special double magnetometer system that the team first tried out at Bath in the 2003 series. Following the initial development and trial, several changes were made, resulting in a new mobile and lightweight system.

'This new design is really useful,' says Ben. 'It's basically just two magnetometers joined together so we can record information twice as fast. But whereas the first system needed to be calibrated at regular intervals and consisted of two normal "mags" on a frame, this new design is specially made and is really easy to use. It only needs to be calibrated once a day and is very lightweight.'

Walking 15 miles a day
So with 'perfect' geology and super new equipment, could the 'geofizz' be any better? 'Well, the results have been good but we still have to walk about 15 miles a day,' says Ben with a smile.

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