Green Waste, A Growing Problem

A relatively new, but increasing, bane for geophysicists and metal detectorists alike, is the practice of spreading green waste on fields. Part of the drive for increased recycling in society, which is good, this material comes from our gardens, but is rarely pure. Many households are not too fussed with what they will put in their bins, so plastic and metal will end up in the green waste. Farmers will buy this from the council and then use it to fertilise their fields. The metal component of this will cause problems for magnetometers, producing white noise from thousands of tiny dipoles. For example, this is a Roman settlement :

This is a Roman villa :

Once it's in there, it's there for good. Metal detectorists get it worse, as they are also picking up non-ferrous material. There is even a blog dedicated to the problem.

Latest Results: Chichester

This year, my biggest project was spending a week within the Chichester town walls, looking for Romans with the GPR. The original purpose of the visit was to test the theory that Stane Street did not start at the east gate, but actually went through the Roman town and out the other side. It soon became clear that the archaeology was too shallow to be visible amongst the modern services. Instead, I ended up surveying some grassed areas to look for signs of the Roman town. This is just a quick summary, but you can read the full report here.

There were two main areas I surveyed. The first was in Priory Park, in the NE corner of the Roman town. The survey revealed two Roman buildings south of the Guildhall and part of the Roman road grid internal to the town to the east, with some low status settlement. The road had been cut in two places by the medieval motte and bailey ditches. You can see a video of the results here and of the two buildings here and here.

Priory Park Interpretation. Click for larger image.

The second area surveyed was the amphitheatre, just to the south-east of the Roman east gate. It isn't in particularly good condition, most of the retaining walls have been robbed, but some structure is still visible. You can see a video of the results here, but on that version, a block of data is shifted from where it should be.

Amphitheatre Interpretation. Click for larger image.

While these are excellent results, they are nothing compared to what is currently being found at Verulamium, where they are using mag and radar to reveal the structure of the town. I'd like to give a shout out to their most excellent blog, which shows the results in great detail. Well worth a read.