20 September 2020

Digging Up The Geophysics: Brough

 Back in 2018, I was asked to do a radar survey over part of the Roman town of Petuaria. I returned in early 2019 to do a second season of geophysics, in peoples gardens surrounding the site, which unfortunately I cannot show here. I also resurveyed the possible theatre building at a higher resolution, and walking perpendicular to the first survey, which showed a number of changes to the original layout.


Second GPR survey over the possible theatre building

Now in 2020, part of the possible threatre has been excavated by Hull University, with a long trench across the building.

Excavation trench, and features within it

At the north end of the trench, the expected floor surface (G on the plan above) was found, though being gravel, it is likely that the radar was not picking up that surface, but the layer of larger stones below it. Some flat stones and tile had been inserted into the floor for use as a hearth.

Floor layer at the north end of the trench

Where the stage was supposed to be (feature F on the plan above), there was a layer of rubble, which was found to be a collapsed wall, as underneath that rubble was a layer of wall plaster that had fallen flat and face down. Wall plaster had been found across the site, with multiple colours found, such as red, black, yellow, green, purple and white. It took a long time to carefully remove the wall plaster in an orderly fashion, which didn't finish until the end of the dig.

Rubble of fallen wall
 
Layer of face down wall plaster
 
A section of lifted wall plaster with paint still attached

Further south, things started to get a bot more murky, and controversial. The identification of the building as a theatre was in part down to the seating area, the D shape shown on the GPR results (feature D on the plan above). The feature was found as a straight, wide and thin (depth) wall. It seemed to have facing stones, and rubble core, and additional unmortared areas of flat stones arranged on both sides. It was also very thin, so would not have been any good at holding a ceiling, but would have been good for holding wooden seating. It was in the right position and right angle and right depth, for the feature seen on the GPR, but it was straight rather than curving, as was expected.

'Wall' feature, part of the 'D' shaped feature?

That wasn't the only problem. The dating material appearing showed the building was 4th century, but the inscription showing the stage being built was robbed to make part of the military wall in the 2nd century, so the inscription could not have been referring to this building. Unfortunately, as sometimes happens when personal theories are challenged, I got rather defensive about this (sorry guys). The current prevailing interpretation is of a courtyard building, and further work is hopefully planned for next year to continue work in the same trench to hopefully resolve the matter further.






26 January 2020

Snuffler Version 1.3 Released

It's been a while since the last version of Snuffler was released. At this stage, the software does most of what I need it to do for my own geophysics work, so this release, version 1.3, is mostly about requests from other people. Apart from the usual bug fixes, the new features mostly deal with hardware changes, especially relating to the RM85 and its use of the earth resistance multiplexer and the FGM650 magnetometer. It's difficult to test these things properly without having the hardware, so I have to rely on my users to help me get it right. It seems my last attempt at dealing with the multiplexer wasn't right.

Another thing reported by some of my users is that Snuffler doesn't work on Windows 10 64bit. To resolve this, I have created a 64bit build of Snuffler, if you are having trouble installing the normal 32bit version.

As usual, the lastest version can be downloaded from here.